I used curl to test my handwritten HTTP 2.0 server. That includes sending chunked, compression support, SSL with the 3 basic auth methods, all the various verbs, etc. I could write curl in a 3 day weekend comfortably.
https://files.mastodon.social/media_attachments/files/114/295/495/418/604/132/original/4e2d7c1b314b105e.png