1.21.0 - Add support for pruning of idle pool connections

What's Changed

Add support for pruning of idle pool connections by @gwynne in #110

EventLoopConnectionPool now supports optional periodic pruning of connections that have been idle for too long. Both the polling interval and the idle timeout are configurable.

Original credit for much of this code goes to @MahdiBM et al—and if I should have the opportunity to credit the et al, I will gladly do so!

Reviewers

Thanks to the reviewers for their help:

• @MahdiBM

This patch was released by @gwynne

Full Changelog: 1.20.0...1.21.0