Fixed the bug that can accept subscription requests during the initialization of WebSocket.

src/http/websocket.rs

@@ -93,6 +93,7 @@ where
     fn poll_next(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Option<Self::Item>> {
         let mut this = self.project();
 
+        if this.init_fut.is_none() {
             while let Poll::Ready(message) = Pin::new(&mut this.stream).poll_next(cx) {
                 let message = match message {
                     Some(message) => message,
@@ -117,6 +118,7 @@ where
                             *this.init_fut = Some(Box::pin(async move {
                                 data_initializer(payload.unwrap_or_default()).await
                             }));
+                            break;
                         }
                     }
                     ClientMessage::Start {
@@ -144,6 +146,7 @@ where
                     ClientMessage::ConnectionTerminate => return Poll::Ready(None),
                 }
             }
+        }
 
         if let Some(init_fut) = this.init_fut {
             if let Poll::Ready(res) = init_fut.poll_unpin(cx) {