ExhaustResponseReader will be a new type returned from NetworkInterface::startExhaustCommand that will allow the controller to dictate when exhaust responses are read from the underlying connection, rather than having the NITL reactor thread do that work. In this ticket, we should implement the type according to the design and add C++ unit or integration tests for it as a component. Integrating it with NITL and ThreadPoolTaskExecutor will happen in a subsequent ticket.