def remove(reader)
      rc = ffi_delegate.remove(reader)
      raise_zmq_err("unable to remove socket %p" % reader) if rc == -1
      forget_socket(reader)
    end
def remove(reader)
      rc = ffi_delegate.remove(reader)
      raise_zmq_err("unable to remove socket %p" % reader) if rc == -1
      forget_socket(reader)
    end
Removes a reader socket from the poller.
 @param reader [Socket, Actor] socket to remove
 @return [void]
 @raise [ArgumentError] if socket was invalid, e.g. it wasn't registered
   in this poller
 @raise [SystemCallError] if this fails for another reason