This is a tool which attempts to brute force a password by making HTTP POSTs to an API? And someone though the best way to write that was in in PHP, which is single threaded and thus cannot try multiple passwords in parallel?
Wow. Ok. Good luck with that.
Also, PHP does have support for multiple threads and/or forking. It's just not commonly used.
Yes, I know PHP can use a standard fork() call. But if you fork, then you need to shard the attack space into different sections, and then pull all the results back together again. Or you manually use `split` on the wordlist and run them as parallel processes. Either way, you are going to have to go through that trouble to re-combining everything. At which point, you might as well use an actual threaded language.
(The only other way I know to do threading in PHP is with curl's multi-request feature, which is hacky and leads to several problems, in addition to head-of-line blocking).