diff --git a/viz-core/src/from_request.rs b/viz-core/src/from_request.rs
index 32f26c48..130e48bc 100644
--- a/viz-core/src/from_request.rs
+++ b/viz-core/src/from_request.rs
@@ -1,9 +1,9 @@
 //! Extracts data from the [`Request`] by types.
 
-use crate::{async_trait, IntoResponse, Request};
+use crate::{IntoResponse, Request};
 
 /// An interface for extracting data from the HTTP [`Request`].
-#[async_trait]
+#[crate::async_trait]
 pub trait FromRequest: Sized {
     /// The type returned in the event of a conversion error.
     type Error: IntoResponse;
@@ -12,7 +12,7 @@ pub trait FromRequest: Sized {
     async fn extract(req: &mut Request) -> Result<Self, Self::Error>;
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<T> FromRequest for Option<T>
 where
     T: FromRequest,
@@ -24,7 +24,7 @@ where
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<T> FromRequest for Result<T, T::Error>
 where
     T: FromRequest,
diff --git a/viz-core/src/handler.rs b/viz-core/src/handler.rs
index 32ebfba9..5bff45dc 100644
--- a/viz-core/src/handler.rs
+++ b/viz-core/src/handler.rs
@@ -1,7 +1,5 @@
 //! Traits and types for handling an HTTP.
 
-use crate::{async_trait, Future};
-
 mod cloneable;
 
 mod after;
@@ -58,7 +56,7 @@ pub use service::ServiceHandler;
 /// A simplified asynchronous interface for handling input and output.
 ///
 /// Composable request handlers.
-#[async_trait]
+#[crate::async_trait]
 pub trait Handler<Input>: Send + Sync + 'static {
     /// The returned type after the call operator is used.
     type Output;
@@ -67,12 +65,12 @@ pub trait Handler<Input>: Send + Sync + 'static {
     async fn call(&self, input: Input) -> Self::Output;
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<F, I, Fut, O> Handler<I> for F
 where
     I: Send + 'static,
     F: Fn(I) -> Fut + ?Sized + Clone + Send + Sync + 'static,
-    Fut: Future<Output = O> + Send + 'static,
+    Fut: ::core::future::Future<Output = O> + Send + 'static,
 {
     type Output = Fut::Output;
 
diff --git a/viz-core/src/handler/after.rs b/viz-core/src/handler/after.rs
index 8964fffe..4b452389 100644
--- a/viz-core/src/handler/after.rs
+++ b/viz-core/src/handler/after.rs
@@ -1,4 +1,4 @@
-use crate::{async_trait, Handler, Result};
+use crate::{Handler, Result};
 
 /// Maps the output `Result<T>` after the handler called.
 #[derive(Debug, Clone)]
@@ -15,13 +15,12 @@ impl<H, F> After<H, F> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, F, I, O> Handler<I> for After<H, F>
 where
     I: Send + 'static,
     H: Handler<I, Output = Result<O>>,
-    F: Handler<H::Output, Output = H::Output> + Clone + 'static,
-    O: 'static,
+    F: Handler<H::Output, Output = H::Output>,
 {
     type Output = F::Output;
 
diff --git a/viz-core/src/handler/and_then.rs b/viz-core/src/handler/and_then.rs
index 6b5b81c2..515388dd 100644
--- a/viz-core/src/handler/and_then.rs
+++ b/viz-core/src/handler/and_then.rs
@@ -1,4 +1,4 @@
-use crate::{async_trait, Handler, Result};
+use crate::{Handler, Result};
 
 /// Calls `op` if the output is `Ok`, otherwise returns the `Err` value of the output.
 #[derive(Debug, Clone)]
@@ -15,7 +15,7 @@ impl<H, F> AndThen<H, F> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, F, I, O> Handler<I> for AndThen<H, F>
 where
     I: Send + 'static,
diff --git a/viz-core/src/handler/around.rs b/viz-core/src/handler/around.rs
index bd928167..2e401964 100644
--- a/viz-core/src/handler/around.rs
+++ b/viz-core/src/handler/around.rs
@@ -1,4 +1,4 @@
-use crate::{async_trait, Handler, Result};
+use crate::{Handler, Result};
 
 /// Represents a middleware parameter, which is a tuple that includes Requset and `BoxHandler`.
 pub type Next<I, H> = (I, H);
@@ -18,13 +18,12 @@ impl<H, F> Around<H, F> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, F, I, O> Handler<I> for Around<H, F>
 where
     I: Send + 'static,
     H: Handler<I, Output = Result<O>> + Clone,
     F: Handler<Next<I, H>, Output = H::Output>,
-    O: 'static,
 {
     type Output = F::Output;
 
diff --git a/viz-core/src/handler/before.rs b/viz-core/src/handler/before.rs
index 5b94bf9d..6eeb901b 100644
--- a/viz-core/src/handler/before.rs
+++ b/viz-core/src/handler/before.rs
@@ -1,4 +1,4 @@
-use crate::{async_trait, Handler, Result};
+use crate::{Handler, Result};
 
 /// Maps the input before the handler calls.
 #[derive(Debug, Clone)]
@@ -15,13 +15,12 @@ impl<H, F> Before<H, F> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, F, I, O> Handler<I> for Before<H, F>
 where
     I: Send + 'static,
     F: Handler<I, Output = Result<I>>,
     H: Handler<I, Output = Result<O>>,
-    O: 'static,
 {
     type Output = H::Output;
 
diff --git a/viz-core/src/handler/boxed.rs b/viz-core/src/handler/boxed.rs
index d1b71e7d..43ea69aa 100644
--- a/viz-core/src/handler/boxed.rs
+++ b/viz-core/src/handler/boxed.rs
@@ -1,7 +1,7 @@
 use std::fmt;
 
 use super::cloneable::BoxCloneable;
-use crate::{async_trait, Handler, Request, Response, Result};
+use crate::{Handler, Request, Response, Result};
 
 /// A [`Clone`] + [`Send`] boxed [`Handler`].
 pub struct BoxHandler<I = Request, O = Result<Response>>(BoxCloneable<I, O>);
@@ -18,7 +18,7 @@ impl<I, O> BoxHandler<I, O> {
 
 impl<I, O> Clone for BoxHandler<I, O>
 where
-    I: 'static,
+    I: Send + 'static,
     O: 'static,
 {
     fn clone(&self) -> Self {
@@ -26,7 +26,7 @@ where
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<I, O> Handler<I> for BoxHandler<I, O>
 where
     I: Send + 'static,
diff --git a/viz-core/src/handler/catch_error.rs b/viz-core/src/handler/catch_error.rs
index cf500c7a..9dc49f68 100644
--- a/viz-core/src/handler/catch_error.rs
+++ b/viz-core/src/handler/catch_error.rs
@@ -1,6 +1,6 @@
 use std::marker::PhantomData;
 
-use crate::{async_trait, Handler, IntoResponse, Response, Result};
+use crate::{Handler, IntoResponse, Response, Result};
 
 /// Catches rejected error while calling the handler.
 #[derive(Debug)]
@@ -36,7 +36,7 @@ impl<H, F, E, R> CatchError<H, F, E, R> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, I, O, F, E, R> Handler<I> for CatchError<H, F, E, R>
 where
     I: Send + 'static,
diff --git a/viz-core/src/handler/catch_unwind.rs b/viz-core/src/handler/catch_unwind.rs
index 5797a52b..6ef08f3f 100644
--- a/viz-core/src/handler/catch_unwind.rs
+++ b/viz-core/src/handler/catch_unwind.rs
@@ -1,4 +1,4 @@
-use crate::{async_trait, future::FutureExt, Handler, IntoResponse, Response, Result};
+use crate::{future::FutureExt, Handler, IntoResponse, Response, Result};
 
 /// Catches unwinding panics while calling the handler.
 #[derive(Debug, Clone)]
@@ -15,7 +15,7 @@ impl<H, F> CatchUnwind<H, F> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, F, I, O, R> Handler<I> for CatchUnwind<H, F>
 where
     I: Send + 'static,
diff --git a/viz-core/src/handler/fn_ext.rs b/viz-core/src/handler/fn_ext.rs
index aa1946f1..a69022dc 100644
--- a/viz-core/src/handler/fn_ext.rs
+++ b/viz-core/src/handler/fn_ext.rs
@@ -1,11 +1,9 @@
-use crate::{async_trait, Request};
-
 /// A handler with extractors.
-#[async_trait]
-pub trait FnExt<E>: Send + Sync + 'static {
+#[crate::async_trait]
+pub trait FnExt<I, E>: Send + Sync + 'static {
     /// The returned type after the call operator is used.
     type Output;
 
     /// Performs the call operation.
-    async fn call(&self, req: Request) -> Self::Output;
+    async fn call(&self, i: I) -> Self::Output;
 }
diff --git a/viz-core/src/handler/fn_ext_hanlder.rs b/viz-core/src/handler/fn_ext_hanlder.rs
index 9d6a6958..08a431e8 100644
--- a/viz-core/src/handler/fn_ext_hanlder.rs
+++ b/viz-core/src/handler/fn_ext_hanlder.rs
@@ -1,6 +1,6 @@
 use std::marker::PhantomData;
 
-use crate::{async_trait, FnExt, FromRequest, Handler, IntoResponse, Request, Result};
+use crate::{FnExt, FromRequest, Handler, IntoResponse, Result};
 
 /// A wrapper of the extractors handler.
 #[derive(Debug)]
@@ -22,17 +22,18 @@ impl<H, E, O> FnExtHandler<H, E, O> {
     }
 }
 
-#[async_trait]
-impl<H, E, O> Handler<Request> for FnExtHandler<H, E, O>
+#[crate::async_trait]
+impl<I, H, E, O> Handler<I> for FnExtHandler<H, E, O>
 where
+    I: Send + 'static,
     E: FromRequest + 'static,
     E::Error: IntoResponse,
-    H: FnExt<E, Output = Result<O>>,
+    H: FnExt<I, E, Output = Result<O>>,
     O: 'static,
 {
     type Output = H::Output;
 
-    async fn call(&self, req: Request) -> Self::Output {
-        self.0.call(req).await.map_err(IntoResponse::into_error)
+    async fn call(&self, i: I) -> Self::Output {
+        self.0.call(i).await.map_err(IntoResponse::into_error)
     }
 }
diff --git a/viz-core/src/handler/into_handler.rs b/viz-core/src/handler/into_handler.rs
index 46d3351d..179dbc9d 100644
--- a/viz-core/src/handler/into_handler.rs
+++ b/viz-core/src/handler/into_handler.rs
@@ -1,7 +1,7 @@
-use crate::{handler::FnExtHandler, FnExt, FromRequest, Handler, IntoResponse, Request, Result};
+use crate::{handler::FnExtHandler, FnExt, FromRequest, Handler, IntoResponse, Result};
 
 /// The trait implemented by types that can be converted to a [`Handler`].
-pub trait IntoHandler<E, I> {
+pub trait IntoHandler<I, E> {
     /// The target handler.
     type Handler: Handler<I>;
 
@@ -10,11 +10,12 @@ pub trait IntoHandler<E, I> {
     fn into_handler(self) -> Self::Handler;
 }
 
-impl<H, E, O> IntoHandler<E, Request> for H
+impl<I, H, E, O> IntoHandler<I, E> for H
 where
+    I: Send + 'static,
     E: FromRequest + 'static,
     E::Error: IntoResponse,
-    H: FnExt<E, Output = Result<O>>,
+    H: FnExt<I, E, Output = Result<O>>,
     O: 'static,
 {
     type Handler = FnExtHandler<H, E, O>;
diff --git a/viz-core/src/handler/map.rs b/viz-core/src/handler/map.rs
index 84f6c1e5..bbb8b45c 100644
--- a/viz-core/src/handler/map.rs
+++ b/viz-core/src/handler/map.rs
@@ -1,4 +1,4 @@
-use crate::{async_trait, Handler, Result};
+use crate::{Handler, Result};
 
 /// Maps the `Ok` value of the output if after the handler called.
 #[derive(Debug, Clone)]
@@ -15,7 +15,7 @@ impl<H, F> Map<H, F> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, F, I, O, T> Handler<I> for Map<H, F>
 where
     I: Send + 'static,
diff --git a/viz-core/src/handler/map_err.rs b/viz-core/src/handler/map_err.rs
index f284ef4b..54ea3f07 100644
--- a/viz-core/src/handler/map_err.rs
+++ b/viz-core/src/handler/map_err.rs
@@ -1,4 +1,4 @@
-use crate::{async_trait, Error, Handler, Result};
+use crate::{Error, Handler, Result};
 
 /// Maps the `Err` value of the output if after the handler called.
 #[derive(Debug, Clone)]
@@ -15,7 +15,7 @@ impl<H, F> MapErr<H, F> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, F, I, O, E> Handler<I> for MapErr<H, F>
 where
     I: Send + 'static,
diff --git a/viz-core/src/handler/map_into_response.rs b/viz-core/src/handler/map_into_response.rs
index 6f62b879..1e871dd7 100644
--- a/viz-core/src/handler/map_into_response.rs
+++ b/viz-core/src/handler/map_into_response.rs
@@ -1,4 +1,4 @@
-use crate::{async_trait, Handler, IntoResponse, Response, Result};
+use crate::{Handler, IntoResponse, Response, Result};
 
 /// Maps the handler's output type to the [`Response`].
 #[derive(Debug, Clone)]
@@ -12,12 +12,12 @@ impl<H> MapInToResponse<H> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, I, O> Handler<I> for MapInToResponse<H>
 where
     I: Send + 'static,
     H: Handler<I, Output = Result<O>>,
-    O: IntoResponse + 'static,
+    O: IntoResponse,
 {
     type Output = Result<Response>;
 
diff --git a/viz-core/src/handler/or_else.rs b/viz-core/src/handler/or_else.rs
index dd5a7ea5..942d6f76 100644
--- a/viz-core/src/handler/or_else.rs
+++ b/viz-core/src/handler/or_else.rs
@@ -1,4 +1,4 @@
-use crate::{async_trait, Error, Handler, Result};
+use crate::{Error, Handler, Result};
 
 /// Calls `op` if the output is `Err`, otherwise returns the `Ok` value of the output.
 #[derive(Debug, Clone)]
@@ -15,13 +15,13 @@ impl<H, F> OrElse<H, F> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, F, I, O> Handler<I> for OrElse<H, F>
 where
     I: Send + 'static,
     H: Handler<I, Output = Result<O>>,
     F: Handler<Error, Output = H::Output>,
-    O: Send + 'static,
+    O: Send,
 {
     type Output = F::Output;
 
diff --git a/viz-core/src/handler/service.rs b/viz-core/src/handler/service.rs
index f2fa97ac..23bf038e 100644
--- a/viz-core/src/handler/service.rs
+++ b/viz-core/src/handler/service.rs
@@ -1,8 +1,6 @@
 use hyper::service::Service;
 
-use crate::{
-    async_trait, Body, BoxError, Bytes, Error, Handler, HttpBody, Request, Response, Result,
-};
+use crate::{Body, BoxError, Bytes, Error, Handler, HttpBody, Request, Response, Result};
 
 /// Converts a hyper [`Service`] to a viz [`Handler`].
 #[derive(Debug, Clone)]
@@ -15,7 +13,7 @@ impl<S> ServiceHandler<S> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<I, O, S> Handler<Request<I>> for ServiceHandler<S>
 where
     I: HttpBody + Send + 'static,
diff --git a/viz-core/src/lib.rs b/viz-core/src/lib.rs
index 4530108d..b6d7d289 100644
--- a/viz-core/src/lib.rs
+++ b/viz-core/src/lib.rs
@@ -58,7 +58,7 @@ pub use thiserror::Error as ThisError;
 
 #[doc(hidden)]
 mod tuples {
-    use super::{async_trait, Error, FnExt, FromRequest, Future, IntoResponse, Request, Result};
+    use super::{Error, FnExt, FromRequest, Future, IntoResponse, Request, Result};
 
     tuple_impls!(A B C D E F G H I J K L);
 }
diff --git a/viz-core/src/macros.rs b/viz-core/src/macros.rs
index 118b39b1..bde2636a 100644
--- a/viz-core/src/macros.rs
+++ b/viz-core/src/macros.rs
@@ -8,7 +8,7 @@ macro_rules! tuple_impls {
     };
     // "Private" internal implementation
     (@impl $( $T:ident )*) => {
-        #[async_trait]
+        #[crate::async_trait]
         impl<$($T,)*> FromRequest for ($($T,)*)
         where
             $($T: FromRequest + Send,)*
@@ -22,8 +22,8 @@ macro_rules! tuple_impls {
             }
         }
 
-        #[async_trait]
-        impl<$($T,)* Fun, Fut, Out> FnExt<($($T,)*)> for Fun
+        #[crate::async_trait]
+        impl<$($T,)* Fun, Fut, Out> FnExt<Request, ($($T,)*)> for Fun
         where
             $($T: FromRequest + Send,)*
             $($T::Error: IntoResponse + Send,)*
diff --git a/viz-core/src/middleware/compression.rs b/viz-core/src/middleware/compression.rs
index 96cd4120..b34a9d03 100644
--- a/viz-core/src/middleware/compression.rs
+++ b/viz-core/src/middleware/compression.rs
@@ -6,7 +6,6 @@ use async_compression::tokio::bufread;
 use tokio_util::io::{ReaderStream, StreamReader};
 
 use crate::{
-    async_trait,
     header::{HeaderValue, ACCEPT_ENCODING, CONTENT_ENCODING, CONTENT_LENGTH},
     Body, Handler, IntoResponse, Request, Response, Result, Transform,
 };
@@ -32,7 +31,7 @@ pub struct CompressionMiddleware<H> {
     h: H,
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, O> Handler<Request> for CompressionMiddleware<H>
 where
     H: Handler<Request, Output = Result<O>>,
diff --git a/viz-core/src/middleware/cookie.rs b/viz-core/src/middleware/cookie.rs
index cdeaaac7..a9f9daf5 100644
--- a/viz-core/src/middleware/cookie.rs
+++ b/viz-core/src/middleware/cookie.rs
@@ -3,7 +3,6 @@
 use std::fmt;
 
 use crate::{
-    async_trait,
     header::{HeaderValue, COOKIE, SET_COOKIE},
     types::{Cookie, CookieJar, CookieKey, Cookies},
     Handler, IntoResponse, Request, Response, Result, Transform,
@@ -80,7 +79,7 @@ impl<H> fmt::Debug for CookieMiddleware<H> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, O> Handler<Request> for CookieMiddleware<H>
 where
     H: Handler<Request, Output = Result<O>>,
diff --git a/viz-core/src/middleware/cors.rs b/viz-core/src/middleware/cors.rs
index 3f0140ad..29e18873 100644
--- a/viz-core/src/middleware/cors.rs
+++ b/viz-core/src/middleware/cors.rs
@@ -3,7 +3,6 @@
 use std::{collections::HashSet, fmt, sync::Arc};
 
 use crate::{
-    async_trait,
     header::{
         HeaderMap, HeaderName, HeaderValue, ACCESS_CONTROL_ALLOW_CREDENTIALS,
         ACCESS_CONTROL_ALLOW_HEADERS, ACCESS_CONTROL_ALLOW_ORIGIN, ACCESS_CONTROL_REQUEST_HEADERS,
@@ -203,7 +202,7 @@ pub struct CorsMiddleware<H> {
     aceh: AccessControlExposeHeaders,
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, O> Handler<Request> for CorsMiddleware<H>
 where
     H: Handler<Request, Output = Result<O>> + Send + Clone + 'static,
diff --git a/viz-core/src/middleware/csrf.rs b/viz-core/src/middleware/csrf.rs
index 72a64193..b2cdfe8b 100644
--- a/viz-core/src/middleware/csrf.rs
+++ b/viz-core/src/middleware/csrf.rs
@@ -5,7 +5,6 @@ use std::{collections::HashSet, fmt, sync::Arc};
 use base64::Engine as _;
 
 use crate::{
-    async_trait,
     header::{HeaderName, HeaderValue, VARY},
     middleware::helper::{CookieOptions, Cookieable},
     Error, FromRequest, Handler, IntoResponse, Method, Request, RequestExt, Response, Result,
@@ -37,7 +36,7 @@ pub enum Store {
 #[derive(Debug, Clone)]
 pub struct CsrfToken(pub String);
 
-#[async_trait]
+#[crate::async_trait]
 impl FromRequest for CsrfToken {
     type Error = Error;
 
@@ -186,7 +185,7 @@ where
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, O, S, G, V> Handler<Request> for CsrfMiddleware<H, S, G, V>
 where
     H: Handler<Request, Output = Result<O>> + Send + Clone + 'static,
diff --git a/viz-core/src/middleware/limits.rs b/viz-core/src/middleware/limits.rs
index 3229f3a7..c16ec60d 100644
--- a/viz-core/src/middleware/limits.rs
+++ b/viz-core/src/middleware/limits.rs
@@ -3,7 +3,7 @@
 #[cfg(feature = "multipart")]
 use std::sync::Arc;
 
-use crate::{async_trait, types, Handler, IntoResponse, Request, Response, Result, Transform};
+use crate::{types, Handler, IntoResponse, Request, Response, Result, Transform};
 
 /// A configuration for [`LimitsMiddleware`].
 #[derive(Debug, Clone)]
@@ -67,7 +67,7 @@ pub struct LimitsMiddleware<H> {
     config: Config,
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, O> Handler<Request> for LimitsMiddleware<H>
 where
     H: Handler<Request, Output = Result<O>>,
diff --git a/viz-core/src/middleware/otel/metrics.rs b/viz-core/src/middleware/otel/metrics.rs
index 6cf1bb55..a981b8c4 100644
--- a/viz-core/src/middleware/otel/metrics.rs
+++ b/viz-core/src/middleware/otel/metrics.rs
@@ -14,10 +14,7 @@ use opentelemetry_semantic_conventions::trace::{
     HTTP_ROUTE, NETWORK_PROTOCOL_VERSION, SERVER_ADDRESS, SERVER_PORT, URL_SCHEME,
 };
 
-use crate::{
-    async_trait, Handler, IntoResponse, Request, RequestExt, Response, ResponseExt, Result,
-    Transform,
-};
+use crate::{Handler, IntoResponse, Request, RequestExt, Response, ResponseExt, Result, Transform};
 
 const HTTP_SERVER_ACTIVE_REQUESTS: &str = "http.server.active_requests";
 const HTTP_SERVER_DURATION: &str = "http.server.duration";
@@ -96,7 +93,7 @@ pub struct MetricsMiddleware<H> {
     response_size: Histogram<u64>,
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, O> Handler<Request> for MetricsMiddleware<H>
 where
     H: Handler<Request, Output = Result<O>>,
diff --git a/viz-core/src/middleware/otel/tracing.rs b/viz-core/src/middleware/otel/tracing.rs
index 7a8818ef..9de8f394 100644
--- a/viz-core/src/middleware/otel/tracing.rs
+++ b/viz-core/src/middleware/otel/tracing.rs
@@ -19,7 +19,6 @@ use opentelemetry_semantic_conventions::trace::{
 };
 
 use crate::{
-    async_trait,
     header::{HeaderMap, HeaderName},
     headers::UserAgent,
     Handler, IntoResponse, Request, RequestExt, Response, ResponseExt, Result, Transform,
@@ -58,7 +57,7 @@ pub struct TracingMiddleware<H, T> {
     tracer: Arc<T>,
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, O, T> Handler<Request> for TracingMiddleware<H, T>
 where
     H: Handler<Request, Output = Result<O>>,
diff --git a/viz-core/src/middleware/session/config.rs b/viz-core/src/middleware/session/config.rs
index 7b8d4cb8..21cd72dd 100644
--- a/viz-core/src/middleware/session/config.rs
+++ b/viz-core/src/middleware/session/config.rs
@@ -5,7 +5,6 @@ use std::{
 };
 
 use crate::{
-    async_trait,
     middleware::helper::{CookieOptions, Cookieable},
     types::{Cookie, Session},
     Error, Handler, IntoResponse, Request, RequestExt, Response, Result, StatusCode, Transform,
@@ -89,7 +88,7 @@ where
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<H, O, S, G, V> Handler<Request> for SessionMiddleware<H, S, G, V>
 where
     H: Handler<Request, Output = Result<O>>,
diff --git a/viz-core/src/request.rs b/viz-core/src/request.rs
index 84ae12ba..70aae7e9 100644
--- a/viz-core/src/request.rs
+++ b/viz-core/src/request.rs
@@ -1,5 +1,5 @@
 use crate::{
-    async_trait, header,
+    header,
     types::{PayloadError, RealIp},
     Body, BodyState, Bytes, FromRequest, Request, Result,
 };
@@ -36,7 +36,7 @@ use crate::types::Session;
 use crate::types::{ParamsError, PathDeserializer, RouteInfo};
 
 /// The [`Request`] Extension.
-#[async_trait]
+#[crate::async_trait]
 pub trait RequestExt: private::Sealed + Sized {
     /// Get URL's schema of this request.
     fn schema(&self) -> Option<&http::uri::Scheme>;
@@ -193,7 +193,7 @@ pub trait RequestExt: private::Sealed + Sized {
     fn realip(&self) -> Option<RealIp>;
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl RequestExt for Request {
     fn schema(&self) -> Option<&http::uri::Scheme> {
         self.uri().scheme()
diff --git a/viz-core/src/response.rs b/viz-core/src/response.rs
index bdd5743c..18ce6a1e 100644
--- a/viz-core/src/response.rs
+++ b/viz-core/src/response.rs
@@ -1,10 +1,10 @@
 use futures_util::Stream;
 use http_body_util::Full;
 
-use crate::{async_trait, header, Body, BoxError, Bytes, Error, Response, Result, StatusCode};
+use crate::{header, Body, BoxError, Bytes, Error, Response, Result, StatusCode};
 
 /// The [`Response`] Extension.
-#[async_trait]
+#[crate::async_trait]
 pub trait ResponseExt: private::Sealed + Sized {
     /// Get the size of this response's body.
     fn content_length(&self) -> Option<u64>;
@@ -186,7 +186,7 @@ pub trait ResponseExt: private::Sealed + Sized {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl ResponseExt for Response {
     fn content_length(&self) -> Option<u64> {
         self.headers()
diff --git a/viz-core/src/types/cookie.rs b/viz-core/src/types/cookie.rs
index d59fd7d6..5199ed34 100644
--- a/viz-core/src/types/cookie.rs
+++ b/viz-core/src/types/cookie.rs
@@ -6,8 +6,7 @@ use std::{
 };
 
 use crate::{
-    async_trait, Error, FromRequest, IntoResponse, Request, RequestExt, Response, StatusCode,
-    ThisError,
+    Error, FromRequest, IntoResponse, Request, RequestExt, Response, StatusCode, ThisError,
 };
 
 pub use ::cookie::{Cookie, CookieJar, SameSite};
@@ -193,7 +192,7 @@ impl Cookies {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl FromRequest for Cookies {
     type Error = CookiesError;
 
diff --git a/viz-core/src/types/form.rs b/viz-core/src/types/form.rs
index dbaa2bcf..9eb14ed9 100644
--- a/viz-core/src/types/form.rs
+++ b/viz-core/src/types/form.rs
@@ -7,7 +7,7 @@ use std::{
 
 use serde::de::DeserializeOwned;
 
-use crate::{async_trait, FromRequest, Request, RequestExt, Result};
+use crate::{FromRequest, Request, RequestExt, Result};
 
 use super::{Payload, PayloadError};
 
@@ -81,7 +81,7 @@ impl<T> Payload for Form<T> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<T> FromRequest for Form<T>
 where
     T: DeserializeOwned,
diff --git a/viz-core/src/types/header.rs b/viz-core/src/types/header.rs
index be81c3b8..27aa4694 100644
--- a/viz-core/src/types/header.rs
+++ b/viz-core/src/types/header.rs
@@ -6,7 +6,7 @@ use std::{
 };
 
 use crate::{
-    async_trait, header,
+    header,
     headers::{self, HeaderMapExt},
     Error, FromRequest, IntoResponse, Request, Response, Result, StatusCode, ThisError,
 };
@@ -66,7 +66,7 @@ where
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<T> FromRequest for Header<T>
 where
     T: headers::Header,
diff --git a/viz-core/src/types/json.rs b/viz-core/src/types/json.rs
index 4ca05130..96a2083a 100644
--- a/viz-core/src/types/json.rs
+++ b/viz-core/src/types/json.rs
@@ -5,9 +5,7 @@ use std::{
     ops::{Deref, DerefMut},
 };
 
-use crate::{
-    async_trait, FromRequest, IntoResponse, Request, RequestExt, Response, ResponseExt, Result,
-};
+use crate::{FromRequest, IntoResponse, Request, RequestExt, Response, ResponseExt, Result};
 
 use super::{Payload, PayloadError};
 
@@ -82,7 +80,7 @@ impl<T> Payload for Json<T> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<T> FromRequest for Json<T>
 where
     T: serde::de::DeserializeOwned,
diff --git a/viz-core/src/types/limits.rs b/viz-core/src/types/limits.rs
index 96e5a753..821fb524 100644
--- a/viz-core/src/types/limits.rs
+++ b/viz-core/src/types/limits.rs
@@ -1,6 +1,6 @@
 use std::{convert::Infallible, sync::Arc};
 
-use crate::{async_trait, FromRequest, Request, RequestExt};
+use crate::{FromRequest, Request, RequestExt};
 
 #[cfg(feature = "form")]
 use super::Form;
@@ -81,7 +81,7 @@ impl Limits {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl FromRequest for Limits {
     type Error = Infallible;
 
diff --git a/viz-core/src/types/multipart.rs b/viz-core/src/types/multipart.rs
index 99d9147d..209e05e6 100644
--- a/viz-core/src/types/multipart.rs
+++ b/viz-core/src/types/multipart.rs
@@ -2,9 +2,7 @@
 
 use form_data::FormData;
 
-use crate::{
-    async_trait, Body, Error, FromRequest, IntoResponse, Request, RequestExt, Response, StatusCode,
-};
+use crate::{Body, Error, FromRequest, IntoResponse, Request, RequestExt, Response, StatusCode};
 
 use super::{Payload, PayloadError};
 
@@ -28,7 +26,7 @@ impl<T> Payload for Multipart<T> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl FromRequest for Multipart {
     type Error = PayloadError;
 
diff --git a/viz-core/src/types/params.rs b/viz-core/src/types/params.rs
index 5eedc294..e5daf16a 100644
--- a/viz-core/src/types/params.rs
+++ b/viz-core/src/types/params.rs
@@ -11,8 +11,7 @@ use std::{
 use serde::de::DeserializeOwned;
 
 use crate::{
-    async_trait, Error, FromRequest, IntoResponse, Request, RequestExt, Response, StatusCode,
-    ThisError,
+    Error, FromRequest, IntoResponse, Request, RequestExt, Response, StatusCode, ThisError,
 };
 
 pub(crate) use de::PathDeserializer;
@@ -77,7 +76,7 @@ impl Params {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<T> FromRequest for Params<T>
 where
     T: DeserializeOwned,
diff --git a/viz-core/src/types/query.rs b/viz-core/src/types/query.rs
index 9984e099..3026e06c 100644
--- a/viz-core/src/types/query.rs
+++ b/viz-core/src/types/query.rs
@@ -7,7 +7,7 @@ use std::{
 
 use serde::de::DeserializeOwned;
 
-use crate::{async_trait, types::PayloadError, FromRequest, Request, RequestExt, Result};
+use crate::{types::PayloadError, FromRequest, Request, RequestExt, Result};
 
 /// Extracts the data from the query string of a URL.
 pub struct Query<T = ()>(pub T);
@@ -64,7 +64,7 @@ where
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<T> FromRequest for Query<T>
 where
     T: DeserializeOwned,
diff --git a/viz-core/src/types/session.rs b/viz-core/src/types/session.rs
index 0a6109a1..10d8d1be 100644
--- a/viz-core/src/types/session.rs
+++ b/viz-core/src/types/session.rs
@@ -14,7 +14,7 @@ use serde_json::{from_value, to_value, Value};
 
 use sessions_core::{Data, State, CHANGED, PURGED, RENEWED, UNCHANGED};
 
-use crate::{async_trait, Error, FromRequest, IntoResponse, Request, RequestExt, StatusCode};
+use crate::{Error, FromRequest, IntoResponse, Request, RequestExt, StatusCode};
 
 /// A session for the current request.
 #[derive(Clone)]
@@ -170,7 +170,7 @@ impl fmt::Debug for Session {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl FromRequest for Session {
     type Error = Infallible;
 
diff --git a/viz-core/src/types/state.rs b/viz-core/src/types/state.rs
index c916fe1b..b4ee6020 100644
--- a/viz-core/src/types/state.rs
+++ b/viz-core/src/types/state.rs
@@ -6,8 +6,8 @@ use std::{
 };
 
 use crate::{
-    async_trait, future::TryFutureExt, handler::Transform, Error, FromRequest, Handler,
-    IntoResponse, Request, RequestExt, Response, Result, StatusCode, ThisError,
+    handler::Transform, Error, FromRequest, Handler, IntoResponse, Request, RequestExt, Response,
+    Result, StatusCode, ThisError,
 };
 
 /// Extracts state from the extensions of a request.
@@ -49,7 +49,7 @@ impl<T> DerefMut for State<T> {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<T> FromRequest for State<T>
 where
     T: Clone + Send + Sync + 'static,
@@ -72,19 +72,19 @@ where
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl<T, H, O> Handler<Request> for State<(T, H)>
 where
     T: Clone + Send + Sync + 'static,
     H: Handler<Request, Output = Result<O>>,
-    O: IntoResponse + 'static,
+    O: IntoResponse,
 {
     type Output = Result<Response>;
 
     async fn call(&self, mut req: Request) -> Self::Output {
         let Self((t, h)) = self;
         req.extensions_mut().insert(t.clone());
-        h.call(req).map_ok(IntoResponse::into_response).await
+        h.call(req).await.map(IntoResponse::into_response)
     }
 }
 
diff --git a/viz-core/src/types/websocket.rs b/viz-core/src/types/websocket.rs
index 8461a345..675446df 100644
--- a/viz-core/src/types/websocket.rs
+++ b/viz-core/src/types/websocket.rs
@@ -6,7 +6,6 @@ use hyper::upgrade::{OnUpgrade, Upgraded};
 use tokio_tungstenite::tungstenite::protocol::Role;
 
 use crate::{
-    async_trait,
     header::{SEC_WEBSOCKET_PROTOCOL, UPGRADE},
     headers::{
         Connection, HeaderMapExt, HeaderValue, SecWebsocketAccept, SecWebsocketKey,
@@ -99,7 +98,7 @@ impl WebSocket {
     }
 }
 
-#[async_trait]
+#[crate::async_trait]
 impl FromRequest for WebSocket {
     type Error = WebSocketError;
 
diff --git a/viz-handlers/src/embed.rs b/viz-handlers/src/embed.rs
index 92a74a2f..87b648a2 100644
--- a/viz-handlers/src/embed.rs
+++ b/viz-handlers/src/embed.rs
@@ -5,7 +5,6 @@ use std::{borrow::Cow, marker::PhantomData};
 use http_body_util::Full;
 use rust_embed::{EmbeddedFile, RustEmbed};
 use viz_core::{
-    async_trait,
     header::{CONTENT_TYPE, ETAG, IF_NONE_MATCH},
     Handler, IntoResponse, Method, Request, RequestExt, Response, Result, StatusCode,
 };
@@ -28,7 +27,7 @@ impl<E> File<E> {
     }
 }
 
-#[async_trait]
+#[viz_core::async_trait]
 impl<E> Handler<Request> for File<E>
 where
     E: RustEmbed + Send + Sync + 'static,
@@ -36,7 +35,7 @@ where
     type Output = Result<Response>;
 
     async fn call(&self, req: Request) -> Self::Output {
-        serve::<E>(self.0.to_string(), req).await
+        serve::<E>(self.0.to_string(), req)
     }
 }
 
@@ -56,7 +55,7 @@ impl<E> Default for Dir<E> {
     }
 }
 
-#[async_trait]
+#[viz_core::async_trait]
 impl<E> Handler<Request> for Dir<E>
 where
     E: RustEmbed + Send + Sync + 'static,
@@ -64,25 +63,22 @@ where
     type Output = Result<Response>;
 
     async fn call(&self, req: Request) -> Self::Output {
-        let path = match req.route_info().params.first().map(|(_, v)| v) {
-            Some(p) => p,
-            None => "index.html",
-        }
-        .to_string();
-
-        serve::<E>(path, req).await
+        serve::<E>(
+            match req.route_info().params.first().map(|(_, v)| v) {
+                Some(p) => p,
+                None => "index.html",
+            }
+            .to_string(),
+            req,
+        )
     }
 }
 
-#[allow(clippy::unused_async)]
-async fn serve<E>(path: String, req: Request) -> Result<Response>
+fn serve<E>(path: String, req: Request) -> Result<Response>
 where
     E: RustEmbed + Send + Sync + 'static,
 {
-    let method = req.method();
-    let headers = req.headers();
-
-    if method != Method::GET {
+    if Method::GET != req.method() {
         Err(StatusCode::METHOD_NOT_ALLOWED.into_error())?;
     }
 
@@ -90,7 +86,8 @@ where
         Some(EmbeddedFile { data, metadata }) => {
             let hash = hex::encode(metadata.sha256_hash());
 
-            if headers
+            if req
+                .headers()
                 .get(IF_NONE_MATCH)
                 .map_or(false, |etag| etag.to_str().unwrap_or("000000").eq(&hash))
             {
diff --git a/viz-handlers/src/prometheus.rs b/viz-handlers/src/prometheus.rs
index 1326281c..53dfd7d3 100644
--- a/viz-handlers/src/prometheus.rs
+++ b/viz-handlers/src/prometheus.rs
@@ -7,7 +7,6 @@ use opentelemetry::{global::handle_error, metrics::MetricsError};
 use prometheus::{Encoder, TextEncoder};
 
 use viz_core::{
-    async_trait,
     header::{HeaderValue, CONTENT_TYPE},
     Handler, IntoResponse, Request, Response, Result, StatusCode,
 };
@@ -31,7 +30,7 @@ impl Prometheus {
     }
 }
 
-#[async_trait]
+#[viz_core::async_trait]
 impl Handler<Request> for Prometheus {
     type Output = Result<Response>;
 
diff --git a/viz-handlers/src/serve.rs b/viz-handlers/src/serve.rs
index 2e2a33d8..bbf19671 100644
--- a/viz-handlers/src/serve.rs
+++ b/viz-handlers/src/serve.rs
@@ -11,7 +11,6 @@ use tokio::io::AsyncReadExt;
 use tokio_util::io::ReaderStream;
 
 use viz_core::{
-    async_trait,
     headers::{
         AcceptRanges, ContentLength, ContentRange, ContentType, ETag, HeaderMap, HeaderMapExt,
         IfMatch, IfModifiedSince, IfNoneMatch, IfUnmodifiedSince, LastModified, Range,
@@ -47,7 +46,7 @@ impl File {
     }
 }
 
-#[async_trait]
+#[viz_core::async_trait]
 impl Handler<Request> for File {
     type Output = Result<Response>;
 
@@ -98,18 +97,17 @@ impl Dir {
     }
 }
 
-#[async_trait]
+#[viz_core::async_trait]
 impl Handler<Request> for Dir {
     type Output = Result<Response>;
 
     async fn call(&self, req: Request) -> Self::Output {
-        let mut path = self.path.clone();
-
         if req.method() != Method::GET {
             Err(Error::MethodNotAllowed)?;
         }
 
         let mut prev = false;
+        let mut path = self.path.clone();
 
         if let Some(param) = req.route_info().params.first().map(|(_, v)| v) {
             let p = percent_encoding::percent_decode_str(param)
diff --git a/viz-tower/src/layer.rs b/viz-tower/src/layer.rs
index ab3e826f..fa3978e8 100644
--- a/viz-tower/src/layer.rs
+++ b/viz-tower/src/layer.rs
@@ -1,5 +1,3 @@
-use viz_core::Transform;
-
 use crate::Middleware;
 
 /// Transforms a Tower layer into Viz Middleware.
@@ -13,7 +11,7 @@ impl<L> Layered<L> {
     }
 }
 
-impl<L, H> Transform<H> for Layered<L>
+impl<L, H> viz_core::Transform<H> for Layered<L>
 where
     L: Clone,
 {
diff --git a/viz-tower/src/lib.rs b/viz-tower/src/lib.rs
index 662d4f9b..94e45b26 100644
--- a/viz-tower/src/lib.rs
+++ b/viz-tower/src/lib.rs
@@ -1,9 +1,7 @@
 //! An adapter that makes a tower [`Service`] into a [`Handler`].
 
 use tower::{Service, ServiceExt};
-use viz_core::{
-    async_trait, Body, BoxError, Bytes, Error, Handler, HttpBody, Request, Response, Result,
-};
+use viz_core::{Body, BoxError, Bytes, Error, Handler, HttpBody, Request, Response, Result};
 
 mod service;
 pub use service::HandlerService;
@@ -25,7 +23,7 @@ impl<S> ServiceHandler<S> {
     }
 }
 
-#[async_trait]
+#[viz_core::async_trait]
 impl<O, S> Handler<Request> for ServiceHandler<S>
 where
     O: HttpBody + Send + 'static,
diff --git a/viz-tower/src/middleware.rs b/viz-tower/src/middleware.rs
index c30c2929..1f868f44 100644
--- a/viz-tower/src/middleware.rs
+++ b/viz-tower/src/middleware.rs
@@ -1,7 +1,5 @@
 use tower::{Layer, Service, ServiceExt};
-use viz_core::{
-    async_trait, Body, BoxError, Bytes, Error, Handler, HttpBody, Request, Response, Result,
-};
+use viz_core::{Body, BoxError, Bytes, Error, Handler, HttpBody, Request, Response, Result};
 
 use crate::HandlerService;
 
@@ -19,7 +17,7 @@ impl<L, H> Middleware<L, H> {
     }
 }
 
-#[async_trait]
+#[viz_core::async_trait]
 impl<O, L, H> Handler<Request> for Middleware<L, H>
 where
     L: Layer<HandlerService<H>> + Send + Sync + 'static,