fix: add token usage

[desaxce]

Changes:

• add token usage for LangChain

To test:

• Run the following snippet against a Literal AI project and notice token counts:

  
  import os
  from literalai import LiteralClient

from langchain_anthropic import ChatAnthropic from langchain.schema.runnable.config import RunnableConfig from langchain.schema import StrOutputParser from langchain.prompts import ChatPromptTemplate

Set ANTHROPIC_API_KEY

literal_client = LiteralClient(api_key="lsk-***")

cb = literal_client.langchain_callback()

prompt = ChatPromptTemplate.from_messages( ['human', 'Tell me a short joke about {topic}'] )

model = ChatAnthropic(model_name="claude-3-5-sonnet-20240620") runnable = prompt | model

res = runnable.invoke( {"topic": "ice cream"}, config=RunnableConfig(callbacks=[cb], run_name="joke") )

[desaxce]

It works with ChatAnthropic(model_name="claude-3-5-sonnet-20240620", streaming=True) too.

[kumar781]

will it work with azureopenai gpt 4o?