def add(reader)
      rc = ffi_delegate.add(reader)
      raise_zmq_err("unable to add socket %p" % reader) if rc == -1
      remember_socket(reader)
    end
def add(reader)
      rc = ffi_delegate.add(reader)
      raise_zmq_err("unable to add socket %p" % reader) if rc == -1
      remember_socket(reader)
    end
Initializes the Poller. At least one reader has to be given.
 @param reader [Socket, Actor] socket to poll for input
 @param readers [Socket, Actor] any additional sockets to poll for input
 Adds another reader socket to the poller.
 @param reader [Socket, Actor] socket to poll for input
 @return [void]
 @raise [SystemCallError] if this fails