*/
  public abstract static class Listener {
    /**
     * Called when the service initially becomes healthy.
     *
     * <p>This will be called at most once after all the services have entered the {@linkplain
     * State#RUNNING running} state. If any services fail during start up or {@linkplain
     * State#FAILED fail}/{@linkplain State#TERMINATED terminate} before all other services have

 * therefore every method of the listener will be called at most once. N.B. The {@link State#FAILED}
 * and {@link State#TERMINATED} states are terminal states, once a service enters either of these
 * states it cannot ever leave them.
 *
 * <p>Implementors of this interface are strongly encouraged to extend one of the abstract classes

   *
   * @since 27.0
   */
  @ForOverride
  protected void doCancelStart() {}

  @CanIgnoreReturnValue
  @Override
  public final Service startAsync() {
    if (monitor.enterIf(isStartable)) {
      try {
        snapshot = new StateSnapshot(STARTING);
        enqueueStartingEvent();
        doStart();
      } catch (Throwable startupFailure) {

   */
  public abstract static class Listener {
    /**
     * Called when the service initially becomes healthy.
     *
     * <p>This will be called at most once after all the services have entered the {@linkplain
     * State#RUNNING running} state. If any services fail during start up or {@linkplain
     * State#FAILED fail}/{@linkplain State#TERMINATED terminate} before all other services have

import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * This class keeps track of all objects being evaluated at the moment.
 * It helps to provide nicer error messages when the evaluation enters an endless cycle (A obtains a value of B which obtains a value of A).
 * <p>
 * Concurrent evaluation of same objects by multiple threads is still allowed.
 * <p>

			switch state {
			case entered:
				if new == trace.GoWaiting {
					state = blocked
				} else {
					state = entered
				}
			case blocked:
				if new == trace.GoRunnable {
					state = runnable
				} else {
					state = entered
				}
			case runnable:
				if new == trace.GoRunning {
					state = running
				} else {
					state = entered
				}
			case running:

  } else {
    // Some control flow ops in TensorFlow Graph have their respective "Ref" ops
    // as well. For example there is Enter and RefEnter op. RefEnter forwards
    // the input ref buffer to output. However both Enter and RefEnter are
    // mapped to tf_executor::EnterOp during import. Check if it is a Ref op to
    // correctly map to the TensorFlow Graph op.
    if (IsRefTypeControlOp(inst)) op_name = "Ref";

            def a = it.askQuestion("enter value", "value")
            def b = it.askQuestion("enter another value", "value")
            [a, b]
        }

        then:
        1 * outputEventBroadcaster.onOutput(_ as UserInputRequestEvent)
        1 * outputEventBroadcaster.onOutput(_) >> { TextQuestionPromptEvent event ->
            assert event.question == "enter value"
        }

  }
  func.return %result : tensor<*xf32>
}

// CHECK-LABEL: func @enter(%{{.*}}: tensor<*xf32>, %{{.*}}: i1) -> tensor<*xf32> {
func.func @enter(%arg0: tensor<*xf32>, %arg1: i1) -> tensor<*xf32> {
  %result = tf_executor.graph {
// CHECK: tf_executor.Enter %{{.*}} frame "some/fra\22me" : tensor<*xf32>
    %res:2 = tf_executor.Enter %arg0 frame "some/fra\"me" : tensor<*xf32>
    tf_executor.fetch %res#0 : tensor<*xf32>
  }

// satisfied, it adjusts the signal context to make it look like the
// signaled thread just called asyncPreempt and resumes the thread.
// asyncPreempt spills all registers and enters the scheduler.
//
// (An alternative would be to preempt in the signal handler itself.
// This would let the OS save and restore the register state and the
// runtime would only need to know how to extract potentially