RunStepStreamEvent

{
    "event": "thread.run.step.created",
    "data": {
        "id": "string",
        "object": "thread.run.step",
        "created_at": 0,
        "assistant_id": "string",
        "thread_id": "string",
        "run_id": "string",
        "type": "message_creation",
        "status": "in_progress",
        "step_details": {
            "type": "message_creation",
            "message_creation": {
                "message_id": "string"
            }
        },
        "last_error": {
            "code": "server_error",
            "message": "string"
        },
        "expired_at": 0,
        "cancelled_at": 0,
        "failed_at": 0,
        "completed_at": 0,
        "metadata": {
            "property1": "string",
            "property2": "string"
        },
        "usage": {
            "completion_tokens": 0,
            "prompt_tokens": 0,
            "total_tokens": 0
        }
    }
}