REST is a set of constraints that, when applied to HTTP, dictates how resources must behave. It is the recommended way to handle requests with Cowboy.
REST is implemented in Cowboy as a protocol upgrade. Once upgraded, the request is handled as a state machine with many optional callbacks describing the resource and modifying the machine's behavior.
@todo Add the beautiful flow diagram here.
@todo Describe the callbacks.
@todo Explain how to use them.