Always recreate the stream instance

This seems to fix problems with flakey tests

Signed-off-by: Mathias L. Baumann <[email protected]>

Author: Marenz

src/frequenz/client/dispatch/_client.py

@@ -55,11 +55,6 @@
 class Client(BaseApiClient[dispatch_pb2_grpc.MicrogridDispatchServiceStub]):
     """Dispatch API client."""
 
-    streams: dict[
-        int, GrpcStreamBroadcaster[StreamMicrogridDispatchesResponse, DispatchEvent]
-    ] = {}
-    """A dictionary of streamers, keyed by microgrid_id."""
-
     def __init__(
         self,
         *,
@@ -225,26 +220,16 @@ def _get_stream(
         self, microgrid_id: int
     ) -> GrpcStreamBroadcaster[StreamMicrogridDispatchesResponse, DispatchEvent]:
         """Get an instance to the streaming helper."""
-        broadcaster = self.streams.get(microgrid_id)
-        # pylint: disable=protected-access
-        if broadcaster is not None and broadcaster._channel.is_closed:
-            # pylint: enable=protected-access
-            del self.streams[microgrid_id]
-            broadcaster = None
-        if broadcaster is None:
-            request = StreamMicrogridDispatchesRequest(microgrid_id=microgrid_id)
-            broadcaster = GrpcStreamBroadcaster(
-                stream_name="StreamMicrogridDispatches",
-                stream_method=lambda: cast(
-                    AsyncIterator[StreamMicrogridDispatchesResponse],
-                    self.stub.StreamMicrogridDispatches(
-                        request, metadata=self._metadata
-                    ),
-                ),
-                transform=DispatchEvent.from_protobuf,
-                retry_strategy=LinearBackoff(interval=1, limit=0),
-            )
-            self.streams[microgrid_id] = broadcaster
+        request = StreamMicrogridDispatchesRequest(microgrid_id=microgrid_id)
+        broadcaster = GrpcStreamBroadcaster(
+            stream_name="StreamMicrogridDispatches",
+            stream_method=lambda: cast(
+                AsyncIterator[StreamMicrogridDispatchesResponse],
+                self.stub.StreamMicrogridDispatches(request, metadata=self._metadata),
+            ),
+            transform=DispatchEvent.from_protobuf,
+            retry_strategy=LinearBackoff(interval=1, limit=0),
+        )
 
         return broadcaster