Luv is a binding to libuv, the cross-platform C library that does
asynchronous I/O in Node.js and runs its main loop.

Besides asynchronous I/O, libuv also supports multiprocessing and
multithreading. Multiple event loops can be run in different threads. libuv also
exposes a lot of other functionality, amounting to a full OS API, and an
alternative to the standard module Unix.