Asynchronous programming

Asynchronous programming has gained a lot of traction in recent years. In Python 3.5, it finally got some syntax features that solidify concepts of asynchronous execution. But it does not mean that asynchronous programming is only possible starting from Python 3.5. A lot of libraries and frameworks were provided a lot earlier, and most of them have origins in the old versions of Python 2. There is even a whole alternate implementation of Python called Stackless (see Chapter 1, Current Status of Python), which concentrated on this single programming approach. Some of these solutions, such as Twisted, Tornado, or Eventlet, still have huge and active communities and are really worth knowing. Anyway, starting from Python 3.5, asynchronous programming is easier than ever before. So it is expected that its built-in asynchronous features will replace the bigger parts of older tools, or external projects will gradually transform into a kind of high-level frameworks based...