vllm support (langextract-vllm)

[wuli666]

Hello! I have followed the guidelines to provide vLLM support for the LangExtract project and created a new package called langextract-vllm.

Project link: https://github.com/wuli666/langextract-vllm

Let me know if there any feedback. Thanks!

[aksg87]

Thanks @wuli666 ! Can you submit a PR to add it to the list of providers?

Example: #202