Support additional headers

[johnd0e]

No description provided.

[leafo]

Could you explain more about why you want this, and why it should be something stored on the client instance?

Thanks

[johnd0e]

Sure.
For example OpenAI-Organization.
And there are some 3rd-party services, that are not exactly openai-compatible, and require extra headers to pass additional info.
E.g. see https://docs.helicone.ai/getting-started/integration-method/openai-proxy

[leafo]

Thanks for the contribution. My only suggestion is that the more_headers argument takes precedence over the instance level headers object, meaning it's merged after the headers object

[johnd0e]

My only suggestion is [...]

Sure. Done