async def start(self, sample_rate: int):
        """This will be called from the input transport when the transport is
        started. It can be used to initialize the filter. The input transport
        sample rate is provided so the filter can adjust to that sample rate.

        """
        pass
This will be called from the input transport when the transport is
        started. It can be used to initialize the filter. The input transport
        sample rate is provided so the filter can adjust to that sample rate.

        
src/pipecat/audio/filters/base_audio_filter.py