Add flush_audio() to PlayHTTTSService

CHANGELOG.md

@@ -9,7 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
-- Added a `flush_audio()` method to `AzureTTSService` and `FishTTSService`.
+- Added a `flush_audio()` method to `AzureTTSService`, `FishTTSService`, and
+  `PlayHTTTSService`.
 
 - Added `set_language()` and `set_model()` to `AzureSTTService` and
   `AssemblySTTService`.

src/pipecat/services/playht.py

@@ -241,6 +241,14 @@ class PlayHTTTSService(InterruptibleTTSService):
         await self.stop_all_metrics()
         self._request_id = None
 
+    async def flush_audio(self):
+        """Flush any pending audio in the buffer.
+
+        PlayHT's API doesn't provide a mechanism for flushing audio buffers,
+        so this method is a no-op.
+        """
+        logger.trace(f"{self}: flush_audio is a no-op for PlayHT")
+
     async def _receive_messages(self):
         async for message in self._get_websocket():
             if isinstance(message, bytes):