v0.1.1: 12/02/2020

- Moved gate functionality to a subpackage
- Configurable gate control handler
- Client middleware
- Preserve CloseIdleConnections in decorated http.RoundTripper instances
- httpmock package now has convenient stretchr/testify/mock integrations
- observe is now a subpackage and exposes middleware
- normalized client and server middleware across the library
- busy functionality is now in its own package and consistently named