code: public void remove(String peerId, Object ctx)
        throws InvalidPhase, TooManyPendingRequests {
      this.mainThread.remove(peerId, ctx);
    }
docs: Removes a peer from the cluster. If you send remove request in
  non-broadcasting phase, the operation will fail.
  
  @param peerId the id of the peer who will be removed from the cluster.
  @param ctx context to be provided to the callback
  @throws ZabException.InvalidPhase if Zab is not in broadcasting phase.
  @throws ZabException.TooManyPendingRequests if there is a pending snapshot
  request.