code: public void setData(byte[] data) throws Exception
      {
          data = Preconditions.checkNotNull(data, "data cannot be null");
          Preconditions.checkState(nodePath.get() != null, "initial create has not been processed. Call waitForInitialCreate() to ensure.");
          this.data.set(Arrays.copyOf(data, data.length));
          if ( isActive() )
          {
              client.setData().inBackground().forPath(getActualPath(), getData());
          }
      }
docs: Set data that node should set in ZK also writes the data to the node. NOTE: it
  is an error to call this method after {@link #start()} but before the initial create
  has completed. Use {@link #waitForInitialCreate(long, TimeUnit)} to ensure initial
  creation.
  
  @param data new data value
  @throws Exception errors