Fix WebRtcStreamerContext to store weakref to a worker object

streamlit_webrtc/__init__.py

@@ -5,6 +5,7 @@
 import logging
 import os
 from typing import Dict, Hashable, NamedTuple, Optional, Union
+import weakref
 
 try:
     from typing import TypedDict
@@ -84,21 +85,26 @@ class WebRtcStreamerState(NamedTuple):
 
 class WebRtcStreamerContext:
     state: WebRtcStreamerState
-    _worker: Optional[WebRtcWorker]
+    _worker_ref: "Optional[weakref.ReferenceType[WebRtcWorker]]"
 
     def __init__(
         self, worker: Optional[WebRtcWorker], state: WebRtcStreamerState
     ) -> None:
-        self._worker = worker
+        self._worker_ref = weakref.ref(worker) if worker else None
         self.state = state
 
+    def get_worker(self) -> Optional[WebRtcWorker]:
+        return self._worker_ref() if self._worker_ref else None
+
     @property
     def video_transformer(self) -> Optional[VideoTransformerBase]:
-        return self._worker.video_transformer if self._worker else None
+        worker = self.get_worker()
+        return worker.video_transformer if worker else None
 
     @property
     def video_receiver(self) -> Optional[VideoReceiver]:
-        return self._worker.video_receiver if self._worker else None
+        worker = self.get_worker()
+        return worker.video_receiver if worker else None
 
 
 def webrtc_streamer(