People that write C and often C++ use libcurl. A better library for C/C++ developers would be nice and I believe it could be written in Rust, although that would be a bit of a pain because then you need to integrate Rust into your build system.
Do you? For building C projects I certainly don't have to build libcurl, it comes packaged and ready to use with my distribution. The same could be the case with a hypothetical HTTP library written in Rust.
Er, I meant, "who uses libcurl when writing NOT in C/C++"