Revert "Merge pull request #66 from zendesk/samshull/efficiently-close-client"

This reverts commit 30ce2e2f8d6616eb2cf6f14297494623d4e0c04b, reversing
changes made to 5a81dae95874e22bee0946e75a247357029211e3.
Merge pull request #77 from zendesk/samshull/revert-async-loop

Revert "Merge pull request #66 from zendesk/samshull/efficiently-close-client"