{"messageStart": {"role": "assistant"}}
{"contentBlockDelta": {"text": "Hello", "contentBlockIndex": 0}}
{"contentBlockDelta": {"text": " world", "contentBlockIndex": 0}}
{"contentBlockStop": {"contentBlockIndex": 0}}
{"messageStop": {"stopReason": "end_turn"}}
{"metadata": {"usage": {"inputTokens": 8, "outputTokens": 2, "totalTokens": 10}}}
