Almost every popular programing environment provides an incredibly unsound shared-memory multithreading library in the distribution, which winds up being heavily used by every other library--even sometimes built-in ones. Javascript in both the browser and not refrains from this, making it generally safe to use not-invented-here code.

In other languages, you could use libuv or tornado or aio or whatever, but it's like throwing away the entire ecosystem and using an obscure language anyway.