Eventlet is a concurrent networking library for Python that allows
you to change how you run your code, not how you write it.

It uses epoll or libevent for highly scalable non-blocking I/O.
Coroutines ensure that the developer uses a blocking style of
programming that is similar to threading, but provide the benefits of
non-blocking I/O. The event dispatch is implicit, which means you
can easily use Eventlet  from the Python interpreter, or as a small
part of a larger application.

It's easy to get started using Eventlet, and easy to convert existing
applications to use it. Start off by looking at the examples,
common design patterns, and the list of basic API primitives.