RunStepDeltaObject(Run step delta object)

Represents a run step delta i.e. any changed fields on a run step during streaming.

{
    "id": "string",
    "object": "thread.run.step.delta",
    "delta": {
        "step_details": {
            "type": "message_creation",
            "message_creation": {
                "message_id": "string"
            }
        }
    }
}