fix(quic): don't report error for gracefully closed connections

Closes quinn's `Endpoint` with `Ok(())`  when `Accept` returns `None`.

Resolves: #4588.
Related: quinn-rs/quinn#1676.

Pull-Request: #4621.

transports/quic/CHANGELOG.md

@@ -1,7 +1,11 @@
 ## 0.9.3 - unreleased
 
+- No longer report error when explicit closing of a QUIC endpoint succeeds.
+  See [PR 4621].
+
 - Support QUIC stateless resets for supported `libp2p_identity::Keypair`s. See [PR 4554].
 
+[PR 4621]: https://github.com/libp2p/rust-libp2p/pull/4621
 [PR 4554]: https://github.com/libp2p/rust-libp2p/pull/4554
 
 ## 0.9.2

transports/quic/src/lib.rs

@@ -91,6 +91,7 @@ pub enum Error {
     Io(#[from] std::io::Error),
 
     /// The task to drive a quic endpoint has crashed.
+    #[deprecated(since = "0.9.3", note = "No longer emitted")]
     #[error("Endpoint driver crashed")]
     EndpointDriverCrashed,
 

transports/quic/src/transport.rs

@@ -588,7 +588,7 @@ impl<P: Provider> Stream for Listener<P> {
                     return Poll::Ready(Some(event));
                 }
                 Poll::Ready(None) => {
-                    self.close(Err(Error::EndpointDriverCrashed));
+                    self.close(Ok(()));
                     continue;
                 }
                 Poll::Pending => {}