event: message_start
data: {"type":"message_start","message":{"id":"msg_03","type":"message","role":"assistant","model":"claude-fixture","usage":{"input_tokens":201}}}

event: content_block_start
data: {"type":"content_block_start","index":0,"content_block":{"type":"text","text":""}}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"42 行。"}}

event: content_block_stop
data: {"type":"content_block_stop","index":0}

event: message_delta
data: {"type":"message_delta","delta":{"stop_reason":"end_turn"},"usage":{"output_tokens":9}}

event: message_stop
data: {"type":"message_stop"}