StreamChoice

{
    "index": 0,
    "delta": {
        "role": "assistant",
        "content": "string",
        "audio": {
            "data": "string",
            "transcript": "string"
        },
        "reasoning_content": "string",
        "tool_calls": [
            {
                "index": 0,
                "id": "string",
                "type": "function",
                "function": {
                    "name": "string",
                    "arguments": "string"
                }
            }
        ]
    },
    "finish_reason": "stop"
}