Refactoring setUserAgent and Removing Guzzle\Http\Utils Guzzle\Http\Client::setUserAgent() now simply accepts a string as input
Moving the request param curl.emit_io to curl options under emit_io
Add X-Cache and X-Cache-Lookup headers to responses
Add Via headers to requests/responses going through the cache plugin
Store cached responses for longer, allowing stales to be served
Handle stale-if-error directive
Adding an ErrorResponse plugin that can throw specific exceptions based on a service description