liboop4 1.0.1-2 (amd64 binary) in ubuntu hirsute

 Liboop is a low-level event loop management library for POSIX-based
 operating systems. It supports the development of modular, multiplexed
 applications which may respond to events from several sources. It
 replaces the "select() loop" and allows the registration of event
 handlers for file and network I/O, timers and signals. Since processes
 use these mechanisms for almost all external communication, liboop can
 be used as a basis for almost any application.