} else if (auto sink = llvm::dyn_cast<tf_executor::NextIterationSinkOp>(op)) {
    return ops_have_same_device(sink.GetSource(), sink);
  }

  return llvm::isa<tf_executor::EnterOp, tf_executor::ExitOp,
                   tf_executor::IslandOp, tf_executor::MergeOp,
                   tf_executor::SwitchOp>(op);
}

// Assigns all data results to a specified device.
void PopulateDeviceForOpResults(

  }

  static void checkNoConflict(
      boolean safe, String conflictDescription, Object entry1, Object entry2) {
    if (!safe) {
      throw conflictException(conflictDescription, entry1, entry2);
    }
  }

  static IllegalArgumentException conflictException(
      String conflictDescription, Object entry1, Object entry2) {
    return new IllegalArgumentException(

	// Note that dumping process will stop the queue-set from proceeding
	// any requests.
	// For debugging only.
	Dump(includeRequestDetails bool) debug.QueueSetDump
}

// QueueNoteFn is called when a request enters and leaves a queue
type QueueNoteFn func(inQueue bool)

// Request represents the remainder of the handling of one request
type Request interface {
	// Finish determines whether to execute or reject the request and

    val id = identities.getId(reference)
    if (id != null) {
        writeSmallInt(id)
    } else {
        val newId = identities.putInstance(reference)
        writeSmallInt(newId)
        circularReferences.enter(reference)
        try {
            encode(reference)
        } finally {
            circularReferences.leave(reference)
        }
    }
}

    }

    private String determineExitHint(BuildRequestMetaData requestContext) {
        if (requestContext.isInteractive()) {
            if (operatingSystem.isWindows()) {
                return " (ctrl-d then enter to exit)";
            } else {
                return " (ctrl-d to exit)";
            }
        } else {
            return "";
        }
    }

		markLastImplicit(&inst, PrefixDataSize)

	case CVTSI2SD, CVTSI2SS:
		if !isMem(inst.Args[1]) {
			markLastImplicit(&inst, PrefixDataSize)
		}

	case CVTSD2SI, CVTSS2SI, CVTTSD2SI, CVTTSS2SI,
		ENTER, FLDENV, FNSAVE, FNSTENV, FRSTOR, LGDT, LIDT, LRET,
		POP, PUSH, RET, SGDT, SIDT, SYSRET, XBEGIN:
		markLastImplicit(&inst, PrefixDataSize)

	case LOOP, LOOPE, LOOPNE, MONITOR:
		markLastImplicit(&inst, PrefixAddrSize)

    eventListener.canceled(this)
  }

  override fun isCanceled(): Boolean = canceled

  override fun execute(): Response {
    check(executed.compareAndSet(false, true)) { "Already Executed" }

    timeout.enter()
    callStart()
    try {
      client.dispatcher.executed(this)
      return getResponseWithInterceptorChain()
    } finally {
      client.dispatcher.finished(this)
    }
  }

  Output init_value = ops::Placeholder(root.WithOpName("init"), DT_FLOAT);
  Output loop_cond = ops::Placeholder(root.WithOpName("init"), DT_BOOL);
  Output enter_value =
      ops::internal::Enter(root.WithOpName("enter"), init_value, "fr");
  ops::Merge iv(root.WithOpName("iv"), {enter_value, enter_value});
  ops::Switch latch(root.WithOpName("latch"), iv.output, loop_cond);

		&metrics.HistogramOpts{
			Subsystem: SchedulerSubsystem,
			Name:      "pod_scheduling_sli_duration_seconds",
			Help:      "E2e latency for a pod being scheduled, from the time the pod enters the scheduling queue and might involve multiple scheduling attempts.",
			// Start with 10ms with the last bucket being [~88m, Inf).
			Buckets:        metrics.ExponentialBuckets(0.01, 2, 20),
			StabilityLevel: metrics.BETA,

func.func @testEnterOp(%arg0: tensor<i64> {tf.device = "/job:localhost/replica:0/task:0/device:TPU:0"}) -> tensor<i64> {
  %0 = tf_executor.graph {
    // CHECK:      tf_executor.Enter
    // CHECK-SAME: device = "/job:localhost/replica:0/task:0/device:TPU:0"
    %1:2 = tf_executor.Enter %arg0 frame "frame" : tensor<i64>
    tf_executor.fetch %1#0 : tensor<i64>
  }
  func.return %0 : tensor<i64>
}

// CHECK-LABEL: func @testExitOp