@NotNull
    Promise<Node> computeAsync() {
      started = true;
      if (isObsolete()) {
        if (LOG.isTraceEnabled()) LOG.debug("obsolete command: ", this);
        return resolvedPromise(null);
      }
      else {
        if (LOG.isTraceEnabled()) LOG.debug("background async command: ", this);
        return computeAsync(object);
      }
    }
@NotNull
    Promise<Node> computeAsync()