Executes a request in a client.
Executes a request in a client. Returns a Future of a Http Response.
Basically the execute method of a HttpExecutable knows how to create the appropriate http request for a request object - ie, query params, post vs get, etc.
The return Http response will then be passed to the response handler for conversion into a request specific return type.
the type of the request object handled by this handler
the type of the response object returned by this handler