Support httpx.AsyncClient for python SDK

[camhendo]

Describe the feature or potential improvement

Right now, you can supply a httpx_client to the Langfuse module on instantiation. This is great, but it means that I can't call async for get_prompt under the high-level API.

It's already supported by the AsyncFernLangfuse object, but just needs to be passed through down the chain of instantiation from the Langfuse object. Right now I have to overwrite the async_api with a custom AsyncFernLangfuse instance to bypass this behavior.

Assuming that eventually, the the python SDK will support dynamically choosing sync/async calls, the idea here is to allow:

• async_httpx_client to be a variable passed through from the Langfuse object __init__ method all the way through the LangfuseResourceManager and into AsyncFernLangfuse

Additional information

No response

[marcklingen]

Please see this thread: https://github.com/orgs/langfuse/discussions/3429

Prompts are available immediately as they are served from the prompt cache: https://langfuse.com/docs/prompt-management/features/caching