* The returned duration is calculated using {@link System#nanoTime()}
     * to ensure monotonic behavior. This duration represents the exact time
     * span between clock initialization and the current instant.
     *
     * @return the duration since clock initialization
     * @see #startInstant()
     * @see #instant()
     */
    public Duration elapsedTime() {
        long elapsedNanos = System.nanoTime() - startNanos;

      Supplier<T> delegate, Duration duration) {
    checkNotNull(delegate);
    // The alternative of `duration.compareTo(Duration.ZERO) > 0` causes J2ObjC trouble.
    checkArgument(
        !duration.isNegative() && !duration.isZero(), "duration (%s) must be > 0", duration);
    return new ExpiringMemoizingSupplier<>(delegate, toNanosSaturated(duration));
  }

  @VisibleForTesting

		config.HelpKV{
			Key:         ReplicationWorkersWait,
			Description: `maximum sleep duration between objects to slow down batch replication operation` + defaultHelpPostfix(ReplicationWorkersWait),
			Optional:    true,
			Type:        "duration",
		},
		config.HelpKV{
			Key:         KeyRotationWorkersWait,
			Description: `maximum sleep duration between objects to slow down batch keyrotation operation` + defaultHelpPostfix(KeyRotationWorkersWait),

				var duration time.Duration
				// Only support UTC normalized timestamps.
				if ts.IsAdjustedToUTC {
					switch {
					case ts.Unit.IsSetNANOS():
						duration = time.Duration(val) * time.Nanosecond
					case ts.Unit.IsSetMILLIS():
						duration = time.Duration(val) * time.Millisecond
					case ts.Unit.IsSetMICROS():
						duration = time.Duration(val) * time.Microsecond
					default:

import java.time.Duration;

/** This class is for {@code com.google.common.util.concurrent} use only! */
@J2ktIncompatible
@GwtIncompatible // java.time.Duration
@IgnoreJRERequirement // We use this method only from within APIs that require a Duration.
final class Internal {

  /**
   * Returns the number of nanoseconds of the given duration without throwing or overflowing.
   *

import com.google.common.annotations.J2ktIncompatible;
import java.time.Duration;

/** This class is for {@code com.google.common.collect} use only! */
@J2ktIncompatible
@GwtIncompatible // java.time.Duration
@IgnoreJRERequirement // We use this method only from within APIs that require a Duration.
final class Internal {

  /**
   * Returns the number of nanoseconds of the given duration without throwing or overflowing.
   *

import com.google.common.annotations.J2ktIncompatible;
import java.time.Duration;

/** This class is for {@code com.google.common.base} use only! */
@J2ktIncompatible
@GwtIncompatible // java.time.Duration
final class Internal {

  /**
   * Returns the number of nanoseconds of the given duration without throwing or overflowing.
   *

   */
  @CanIgnoreReturnValue
  @J2ktIncompatible
  @GwtIncompatible // java.time.Duration
  @ParametricNullness
  @IgnoreJRERequirement // Users will use this only if they're already using Duration.
  public static <V extends @Nullable Object> V getUninterruptibly(
      Future<V> future, Duration timeout) throws ExecutionException, TimeoutException {

  }

  static class DurationSpec {
    private final long duration;
    private final TimeUnit unit;

    private DurationSpec(long duration, TimeUnit unit) {
      this.duration = duration;
      this.unit = unit;
    }

    public static DurationSpec of(long duration, TimeUnit unit) {
      return new DurationSpec(duration, unit);
    }

    @Override
    public int hashCode() {

      Supplier<T> delegate, Duration duration) {
    checkNotNull(delegate);
    // The alternative of `duration.compareTo(Duration.ZERO) > 0` causes J2ObjC trouble.
    checkArgument(
        !duration.isNegative() && !duration.isZero(), "duration (%s) must be > 0", duration);
    return new ExpiringMemoizingSupplier<>(delegate, toNanosSaturated(duration));
  }

  @VisibleForTesting