Requests an element on the given port. Calling this method twice before an element arrived will fail. There can only be one outstanding request at any given time.The method HasBeenPulled(Inlet) can be used query whether pull is allowed to be called or not.This method will also fail if the port is already closed.

Requests an element on the given port. Calling this method twice before an element arrived will fail. There can only be one outstanding request at any given time.The method HasBeenPulled(Inlet) can be used query whether pull is allowed to be called or not.This method will also fail if the port is already closed.