refactor!: Use ConnectionError when possible

This changes the public `Endpoint` methods `connect_to` and
`open_bidirectional_stream` to use `ConnectionError` for errors. This
reduces the scope of errors for callers to handle, and sets us up for
further reductions with other methods.

BREAKING CHANGE: `Endpoint::connect_to` and
`Endpoint::open_bidirectional_stream` now use `ConnectionError`, rather
than `Error`, for error results.

src/connections.rs

@@ -11,7 +11,7 @@ use crate::Endpoint;
 
 use super::{
     connection_pool::{ConnId, ConnectionPool, ConnectionRemover},
-    error::{Error, Result},
+    error::{ConnectionError, Error, Result},
     wire_msg::WireMsg,
 };
 use bytes::Bytes;
@@ -45,7 +45,10 @@ impl<I: ConnId> Connection<I> {
     }
 
     /// Priority default is 0. Both lower and higher can be passed in.
-    pub(crate) async fn open_bi(&self, priority: i32) -> Result<(SendStream, RecvStream)> {
+    pub(crate) async fn open_bi(
+        &self,
+        priority: i32,
+    ) -> Result<(SendStream, RecvStream), ConnectionError> {
         let (send_stream, recv_stream) = self.handle_error(self.quic_conn.open_bi().await).await?;
         let send_stream = SendStream::new(send_stream);
         send_stream.set_priority(priority);

src/endpoint.rs

@@ -369,7 +369,7 @@ impl<I: ConnId> Endpoint<I> {
     /// When sending a message on `Connection` fails, the connection is also automatically removed
     /// from the pool and the subsequent call to `connect_to` is guaranteed to reopen new connection
     /// too.
-    pub async fn connect_to(&self, node_addr: &SocketAddr) -> Result<()> {
+    pub async fn connect_to(&self, node_addr: &SocketAddr) -> Result<(), ConnectionError> {
         let _ = self.get_or_connect_to(node_addr).await?;
         Ok(())
     }
@@ -468,7 +468,7 @@ impl<I: ConnId> Endpoint<I> {
         &self,
         peer_addr: &SocketAddr,
         priority: i32,
-    ) -> Result<(SendStream, RecvStream)> {
+    ) -> Result<(SendStream, RecvStream), ConnectionError> {
         let connection = self.get_or_connect_to(peer_addr).await?;
         connection.open_bi(priority).await
     }