websocket: add a wrapper around is_terminated (#3443)

Co-authored-by: Loic <[email protected]>
Co-authored-by: loikki <[email protected]>

axum/src/extract/ws.rs

@@ -94,7 +94,7 @@ use self::rejection::*;
 use super::FromRequestParts;
 use crate::{body::Bytes, response::Response, Error};
 use axum_core::body::Body;
-use futures_core::Stream;
+use futures_core::{FusedStream, Stream};
 use futures_sink::Sink;
 use futures_util::{sink::SinkExt, stream::StreamExt};
 use http::{
@@ -530,6 +530,13 @@ impl WebSocket {
     }
 }
 
+impl FusedStream for WebSocket {
+    /// Returns true if the websocket has been terminated.
+    fn is_terminated(&self) -> bool {
+        self.inner.is_terminated()
+    }
+}
+
 impl Stream for WebSocket {
     type Item = Result<Message, Error>;