closed when receiving binary data from php even if there is no code inside listen function

[glennmichaelmejias]

rdchannel = WebSocketChannel.connect(wsUrl);

    rdchannel!.stream.listen((dynamic v) {
    
    
    } 
    

the binary data is generated in python

for i in range(8):
            for j in range(8):
                chunk_id = i * 8 + j
                left = j * chunk_width
                upper = i * chunk_height
                right = left + chunk_width
                lower = upper + chunk_height
                chunk_img = img.crop((left, upper, right, lower))
                chunk_bytes = io.BytesIO()
                chunk_img.save(chunk_bytes, format='JPEG', quality=quality)
                # Compare with the previous chunk to detect changes
                if prev_chunks.get(chunk_id) != chunk_bytes.getvalue():
                    prev_chunks[chunk_id] = chunk_bytes.getvalue()  # Update the cached chunk
                    # Prepend chunk_id to the binary data
                    chunk_with_id = struct.pack('>I', chunk_id) + chunk_bytes.getvalue()
                    changed_chunks.append(chunk_with_id)  #

        # Send only changed chunks as binary
        if changed_chunks:
            print("sent")
            for chunk in changed_chunks:
                ws.send(chunk, opcode=0x2)  

and there is no manipulation in php server, it just directly send to flutter when its received

E/flutter (31979): [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: SocketException: Reading from a closed socket
E/flutter (31979): #0 _RawSecureSocket.read (dart:io/secure_socket.dart:779:7)
E/flutter (31979): #1 _Socket._onData (dart:io-patch/socket_patch.dart:2448:28)
E/flutter (31979): #2 _RootZone.runUnaryGuarded (dart:async/zone.dart:1594:10)
E/flutter (31979): #3 _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:339:11)
E/flutter (31979): #4 _BufferingStreamSubscription._add (dart:async/stream_impl.dart:271:7)
E/flutter (31979): #5 _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:784:19)
E/flutter (31979): #6 _StreamController._add (dart:async/stream_controller.dart:658:7)
E/flutter (31979): #7 _StreamController.add (dart:async/stream_controller.dart:606:5)
E/flutter (31979): #8 _RawSecureSocket._sendReadEvent (dart:io/secure_socket.dart:1116:19)
E/flutter (31979): #9 Timer._createTimer. (dart:async-patch/timer_patch.dart:18:15)
E/flutter (31979): #10 _Timer._runTimers (dart:isolate-patch/timer_impl.dart:398:19)
E/flutter (31979): #11 _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:429:5)
E/flutter (31979): #12 _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)