Provides interface to libevent library
This is an extension to efficiently schedule I/O, time and signal based
  events using the best I/O notification mechanism available for specific platform.
  This is a port of libevent to the PHP infrastructure.
  Version 1.0.0 introduces:
  * new OO API breaking backwards compatibility
  * support of libevent 2+ including HTTP, DNS, OpenSSL and the event listener.
  Note, event-1.0.0 and greater is not compatible with previous versions.
License: PHP