event: message_start
data: {"type":"message_start","message":{"id":"msg_unk","model":"claude-opus-4-7","usage":{"input_tokens":7,"output_tokens":0,"cache_creation_input_tokens":0,"cache_read_input_tokens":0}}}

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

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"start"}}

event: future_event
data: {"unknown":"payload","added_in":"2026-Q3"}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"middle"}}

event: another_future_event
data: {"v":42}

event: content_block_delta
data: {"type":"content_block_delta","index":0,"delta":{"type":"text_delta","text":"end"}}

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":3}}

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

