Hi, would it be possible to add an extra_body parameter to the OpenAI client's chat completion request, similar to the official Python client?

This would allow passing custom parameters (e.g., beta features) directly to the OpenAI API, improving flexibility without requiring library updates for every new parameter.

ExtraBody: map[string]interface{}{
    "parallel_tool_claims": false,
}

This keeps the client future-proof. Open to feedback and happy to contribute if this is acceptable. Thanks!