feat: add IncomingConnections::try_recv()

This enables a non-blocking method to check for incoming connections
and messages.

This can be useful when using multiple Endpoint in one process or
even one thread.

src/endpoint.rs

@@ -25,7 +25,7 @@ use std::{
     sync::Arc,
 };
 use tokio::sync::broadcast::{self, Sender};
-use tokio::sync::mpsc::{self, Receiver as MpscReceiver};
+use tokio::sync::mpsc::{self, error::TryRecvError, Receiver as MpscReceiver};
 use tokio::time::{timeout, Duration};
 use tracing::{error, info, trace, warn};
 
@@ -49,6 +49,12 @@ impl IncomingConnections {
     pub async fn next(&mut self) -> Option<(Connection, ConnectionIncoming)> {
         self.0.recv().await
     }
+
+    /// Non-blocking method to receive the next incoming connection if present.
+    /// See tokio::sync::mpsc::Receiver::try_recv()
+    pub fn try_recv(&mut self) -> Result<(Connection, ConnectionIncoming), TryRecvError> {
+        self.0.try_recv()
+    }
 }
 
 /// Endpoint instance which can be used to communicate with peers.