code: public void removeNodeStateListener(NodeStateListener listener)
      {
          stateCheck(State.CREATED, State.RUNNING, State.SHUTTING_DOWN, State.QUEUING);
          try
          {
              stateListeners.remove(listener);
              nodeListLock.readLock().lock();
              for (RiakNode node : nodeList)
              {
                  node.removeStateListener(listener);
              }
          }
          finally
          {
              nodeListLock.readLock().unlock();
          }
      }
docs: Remove a NodeStateListener.
  <p>
  The supplied NodeStateListener will be unregistered and no longer
  receive state updates.
  </p>
  @param listener The NodeStateListener to unregister.