*/
    void onError(String phase, String error);

    /**
     * Returns a no-op callback implementation.
     *
     * @return a callback that does nothing
     */
    static ChatPhaseCallback noOp() {
        return new ChatPhaseCallback() {
            @Override
            public void onPhaseStart(final String phase, final String message) {
                // no-op
            }

            @Override

    @Override
    protected void doStart() {
      notifyStarted();
    }

    @Override
    protected void doStop() {
      notifyStopped();
    }
  }

  /*
   * A NoOp service that will delay the startup and shutdown notification for a configurable amount
   * of time.
   */
  private static class NoOpDelayedService extends NoOpService {
    private final long delay;

    @Override
    protected void doStart() {
      notifyStarted();
    }

    @Override
    protected void doStop() {
      notifyStopped();
    }
  }

  /*
   * A NoOp service that will delay the startup and shutdown notification for a configurable amount
   * of time.
   */
  private static class NoOpDelayedService extends NoOpService {
    private final long delay;

	NGCW R13, R8                               // e8030d5a
	NGC R2, R7                                 // e70302da
	NGCSW R10, R5                              // e5030a7a
	NGCS R24, R16                              // f00318fa
	NOOP                                        // 1f2003d5
	ORNW R4@>11, R16, R3                       // 032ee42a
	ORN R22@>19, R3, R3                        // 634cf6aa
	ORRW $4294443071, R15, R24                 // f8490d32

	PRFM	48(R6), PSTL2STRM               // d31880f9
	PRFM	8(R12), PLIL3STRM               // 8d0580f9
	PRFM	(R8), $25                       // 190180f9
	PRFM	8(R9), $30                      // 3e0580f9
	NOOP                                    // 1f2003d5
	HINT $0                                 // 1f2003d5
	DMB	$1
	SVC
	SB                                      // ff3003d5

// encryption

      from both the node defs and the function defs of the graph. Note that
      this currently only strips the `Assert` nodes from the graph and
      converts them into `NoOp`s instead.

*   `tf.data`

    * `tf.data` now has an `autotune_options.initial_parallelism` option to
      control the initial parallelism setting used by autotune before the data