Eric

input_tokens could be None when calculate ussage (Anthropic service）

3

### pipecat version 0.0.67 ### Python version 3.11 ### Operating System mac ### Issue description  2025-05-20 16:56:23.768 | ERROR | pipecat.services.anthropic.llm:_process_context:260 - input_tokens为None，原始event: RawMessageDeltaEvent(delta=Delta(stop_reason='end_turn', stop_sequence=None), type='message_delta', usage=MessageDeltaUsage(cache_creation_input_tokens=None, cache_read_input_tokens=None, input_tokens=None,...