code: public byte[] getMemberData(String memberId)
        throws ZooKeeperConnectionException, KeeperException, InterruptedException {
      return zkClient.get().getData(getMemberPath(memberId), false, null);
    }
docs: Gets the data for one of this groups members by querying ZooKeeper synchronously.
  
  @param memberId the id of the member whose data to retrieve
  @return the data associated with the {@code memberId}
  @throws ZooKeeperConnectionException if there was a problem connecting to ZooKeeper
  @throws KeeperException if there was a problem reading this member's data
  @throws InterruptedException if this thread is interrupted retrieving the member data