AudioBufferProcessor: call callback on CancelFrame

CHANGELOG.md

@@ -69,6 +69,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Fixed an issue in `AudioBufferProcessor` where user callback would not be
+  called on task cancellation.
+
 - Fixed an issue where `ElevenLabsTTSService` messages would return a 1009
   websocket error by increasing the max message size limit to 16MB.
 

src/pipecat/processors/audio/audio_buffer_processor.py

@@ -91,7 +91,7 @@ class AudioBufferProcessor(FrameProcessor):
         if self._buffer_size > 0 and len(self._user_audio_buffer) > self._buffer_size:
             await self._call_on_audio_data_handler()
 
-        if isinstance(frame, EndFrame):
+        if isinstance(frame, (CancelFrame, EndFrame)):
             await self._call_on_audio_data_handler()
 
         await self.push_frame(frame, direction)