ChrisTho23

This is work in progress. Before merging, potential bugs (https://linear.app/langfuse/issue/LF-1519/llamaindex-bug-decorator-are-not-detecting-generations-and-not-logging, https://linear.app/langfuse/issue/LF-1518/llamaindex-bug-single-llm-call-creates-two-traces, https://linear.app/langfuse/issue/LF-1517/llamaindex-bug-settingcallback-manager-does-not-work) have to be reviewed/fixed and results have to be discussed.

For the cookbook to run, one has to install a langfuse version that supports decorators (e.g, 2.20.2a3)

Note that example 1 and 2 in this issue are also very good examples of interoperability although they do not log to Langfuse due to a bug with the LlamaIndex...

Please note, this coobook uses the `get_langchain_prompt()` utility method. This might obviously be a little confusing. Thus, I suggest to rename the method as it is not Langfuse specific and...

Note that example 1 here is a nicer implementation but does not work due to a bug with the callback handler (https://linear.app/langfuse/issue/LFE-649/llamaindex-callback-not-working-once-defining-llm)

Test file was renamed but exemplary test comment in readme not