Lift this request reader into a singleton shapeless.HList and compose it with the given
that
request reader.
Converts this request reader to one that returns any type with B :: HNil
as
its representation.
Applies a function to the result of this reader.
Applies a function returning a future to the result of this reader.
Implicit class that provides
::
and other operations on any request reader to support building shapeless.HList request readers.