Functions for working with [[com.twitter.finagle.http.Message]] and its concrete subclasses,
[[com.twitter.finagle.http.Request]] and [[com.twitter.finagle.http.Response]].

`Request` objects are passed to services bound to a Finagle HTTP server, and `Response` objects must be passed back
(wrapped in a `Future`) in turn. Most requests are constructed by Finagle, but the functions here to may be helpful
to create `MockRequest`s for service testing purposes.