Feature request: Use sendfile() to serve static file if sendfile() available.

TFileOutput class in unit lwebserver.pp serve static file request by reading file content and write it to socket. For unixes, It should use sendfile() for better performance.

Hey, good suggestion. I don't do active development on lNet anymore, but if you'll make a PR I'll be happy to review/apply.

Sure. I'll look into it.