[langchain] token counts missing for gemini + langchain

[mikeldking]

see https://arize-ai.slack.com/archives/C04R3GXC8HK/p1742373744925739

We might not be looking at the right place for token counts.

[satyadevai]

@mikeldking Can you add more context on this ticket? so that I can take up.

[mikeldking]

Hey @satya-turing - I think the first step is to get a small example with gemini + langchain up in say the examples directory.

After that test different types of generation (chat complete, stream, etc.). You will probably find that the token details are somewhere in the langchain run kwargs or extras. Parse those into our conventions!

[Jgilhuly]

Based on Satya's testing, we do collect token counts using the gemini+langchain combo currently. Here's an example: #1456

@mikeldking - lmk if we can close this out

[satyadevai]

Closing this issue due to no updates over the past few weeks.
If you experience any further problems or have additional questions, please feel free to reopen the ticket. Thanks!