chore: direct append data to bufio.Reader's internal buffer as much as possible

transport/vmess/websocket.go

@@ -554,7 +554,14 @@ func StreamUpgradedWebsocketConn(w http.ResponseWriter, r *http.Request) (net.Co
 	}
 
 	if edBuf := decodeXray0rtt(r.Header); len(edBuf) > 0 {
-		conn = N.NewCachedConn(conn, edBuf)
+		appendOk := false
+		if bufConn, ok := conn.(*N.BufferedConn); ok {
+			appendOk = bufConn.AppendData(edBuf)
+		}
+		if !appendOk {
+			conn = N.NewCachedConn(conn, edBuf)
+		}
+
 	}
 
 	return conn, nil