Streaming output

{
    "candidates": [
        {
            "content": {
                "parts": [
                    {
                        "text": "string"
                    }
                ],
                "role": "string"
            },
            "index": 0
        }
    ],
    "usageMetadata": {
        "promptTokenCount": 0,
        "candidatesTokenCount": 0,
        "totalTokenCount": 0,
        "promptTokensDetails": [
            {
                "modality": "string",
                "tokenCount": 0
            }
        ],
        "thoughtsTokenCount": 0
    },
    "modelVersion": "string",
    "responseId": "string"
}