Boost.Beast has its own HTTP parser[0], during the development of which Vinnie Falco (the principle author of Beast) found many bugs/inconsistencies in Node.js's own parser[1].
Personally I'd rather use this than something based on Node.js http-parser.
[0] https://www.boost.org/doc/libs/develop/libs/beast/doc/html/b...
[1] https://github.com/nodejs/http-parser/issues?q=is%3Aissue+au...