v0.0.40

### Added

- VAD parameters can now be dynamicallt updated using the `VADParamsUpdateFrame`.

- `ErrorFrame` has now a `fatal` field to indicate the bot should exit if a fatal error is pushed upstream (false by default). A new `FatalErrorFrame` that sets this flag to true has been added.

- `AnthropicLLMService` now supports function calling and initial support for prompt caching.
  (see https://www.anthropic.com/news/prompt-caching)

- `ElevenLabsTTSService` can now specify ElevenLabs input parameters such as `output_format`.

- `TwilioFrameSerializer` can now specify Twilio's and Pipecat's desired sample rates to use.

- Added new `on_participant_updated` event to `DailyTransport`.

- Added `DailyRESTHelper.delete_room_by_name()` and `DailyRESTHelper.delete_room_by_url()`.

- Added LLM and TTS usage metrics. Those are enabled when `PipelineParams.enable_usage_metrics` is True.

- `AudioRawFrame`s are now pushed downstream from the base output transport. This allows capturing the exact words the bot says by adding an STT service at the end of the pipeline.

- Added new `GStreamerPipelineSource`. This processor can generate image or audio frames from a GStreamer pipeline (e.g. reading an MP4 file, and RTP stream or anything supported by GStreamer).

- Added `TransportParams.audio_out_is_live`. This flag is False by default and it is useful to indicate we should not synchronize audio with sporadic images.

- Added new `BotStartedSpeakingFrame` and `BotStoppedSpeakingFrame` control frames. These frames are pushed upstream and they should wrap `BotSpeakingFrame`.

- Transports now allow you to register event handlers without decorators.

### Changed

- Support RTVI message protocol 0.1. This includes new messages, support for messages responses, support for actions, configuration, webhooks and a bunch of new cool stuff.
  (see https://docs.rtvi.ai/)

- `SileroVAD` dependency is now imported via pip's `silero-vad` package.

- `ElevenLabsTTSService` now uses `eleven_turbo_v2_5` model by default.

- `BotSpeakingFrame` is now a control frame.

- `StartFrame` is now a control frame similar to `EndFrame`.

- `DeepgramTTSService` now is more customizable. You can adjust the encoding and sample rate.

### Fixed

- `TTSStartFrame` and `TTSStopFrame` are now sent when TTS really starts and stops. This allows for knowing when the bot starts and stops speaking even with asynchronous services (like Cartesia).

- Fixed `AzureSTTService` transcription frame timestamps.

- Fixed an issue with `DailyRESTHelper.create_room()` expirations which would cause this function to stop working after the initial expiration elapsed.

- Improved `EndFrame` and `CancelFrame` handling. `EndFrame` should end things gracefully while a `CancelFrame` should cancel all running tasks as soon as possible.

- Fixed an issue in `AIService` that would cause a yielded `None` value to be processed.

- RTVI's `bot-ready` message is now sent when the RTVI pipeline is ready and a first participant joins.

- Fixed a `BaseInputTransport` issue that was causing incoming system frames to be queued instead of being pushed immediately.

- Fixed a `BaseInputTransport` issue that was causing start/stop interruptions incoming frames to not cancel tasks and be processed properly.

### Other

- Added `studypal` example (from to the Cartesia folks!).

- Most examples now use Cartesia.

- Added examples `foundational/19a-tools-anthropic.py`, `foundational/19b-tools-video-anthropic.py` and `foundational/19a-tools-togetherai.py`.

- Added examples `foundational/18-gstreamer-filesrc.py` and `foundational/18a-gstreamer-videotestsrc.py` that show how to use `GStreamerPipelineSource`.

- Remove `requests` library usage.

- Cleanup examples and use `DailyRESTHelper`.