Asynchronous Programming in PHP

PHP is, in many communities, scorned and even trivialized for many reasons---a lack of asynchrony being one of the biggest detractions. Fallacies as egregious as the aforestated derision are intolerable because of the language's current robustness. Asynchrony---using interleaved processes in a single thread---is available to users of the PHP language to address the inefficiencies of inherently slow input/output operations. We can implement it either via language modules like Swoole or idiomatic PHP solutions like ReactPHP and Amp.