// the extra memory consumption and indirection are more
      // expensive than the extra volatile reads.
      long nanos = expirationNanos;
      long now = System.nanoTime();
      if (nanos == 0 || now - nanos >= 0) {
        synchronized (this) {
          if (nanos == expirationNanos) { // recheck for lost race
            T t = delegate.get();
            value = t;

                  @Override
                  protected Set<AnEnum> create(AnEnum[] elements) {
                    AnEnum[] otherElements = new AnEnum[elements.length - 1];
                    System.arraycopy(elements, 1, otherElements, 0, otherElements.length);
                    return Sets.immutableEnumSet(elements[0], otherElements);
                  }
                })
            .named("Sets.immutableEnumSet")

      }
    }
  }

  private static List<Object> subListCopy(Object[] source, int size) {
    final Object[] copy = new Object[size];
    System.arraycopy(source, 0, copy, 0, size);
    return Arrays.asList(copy);
  }

  private interface IteratorOperation {
    @Nullable Object execute(Iterator<?> iterator);
  }

  /**

  private static final BigInteger BAD_FOR_GINGERBREAD_Q = new BigInteger("-4294967296");

  @GwtIncompatible // TODO
  @AndroidIncompatible // slow
  public void testDivNonZeroExact() {
    String runtimeName = System.getProperty("java.runtime.name");
    boolean isAndroid = runtimeName != null && runtimeName.contains("Android");
    for (BigInteger p : NONZERO_BIGINTEGER_CANDIDATES) {
      for (BigInteger q : NONZERO_BIGINTEGER_CANDIDATES) {

  private static final BigInteger BAD_FOR_GINGERBREAD_Q = new BigInteger("-4294967296");

  @GwtIncompatible // TODO
  @AndroidIncompatible // slow
  public void testDivNonZeroExact() {
    String runtimeName = System.getProperty("java.runtime.name");
    boolean isAndroid = runtimeName != null && runtimeName.contains("Android");
    for (BigInteger p : NONZERO_BIGINTEGER_CANDIDATES) {
      for (BigInteger q : NONZERO_BIGINTEGER_CANDIDATES) {

    }

    @CanIgnoreReturnValue
    Builder<K, V> combine(ImmutableSortedMap.Builder<K, V> other) {
      ensureCapacity(size + other.size);
      System.arraycopy(other.keys, 0, this.keys, this.size, other.size);
      System.arraycopy(other.values, 0, this.values, this.size, other.size);
      size += other.size;
      return this;
    }

    /**
     * Returns a newly-created immutable sorted map.

    Comparable<?>[] contents = new Comparable<?>[6 + remaining.length];
    contents[0] = e1;
    contents[1] = e2;
    contents[2] = e3;
    contents[3] = e4;
    contents[4] = e5;
    contents[5] = e6;
    System.arraycopy(remaining, 0, contents, 6, remaining.length);
    return construct(Ordering.natural(), contents.length, (E[]) contents);
  }

  // TODO(kevinb): Consider factory methods that reject duplicates

  /**

    if (future.isDone()) {
      return;
    }
    long timeoutSeconds = timeoutSeconds();
    long deadline = System.nanoTime() + SECONDS.toNanos(timeoutSeconds);
    do {
      System.runFinalization();
      if (future.isDone()) {
        return;
      }
      System.gc();
      try {
        future.get(1L, SECONDS);
        return;
      } catch (CancellationException | ExecutionException ok) {

    else super.runTest();
  }

  protected void runTestProfiled() throws Throwable {
    long t0 = System.nanoTime();
    try {
      super.runTest();
    } finally {
      long elapsedMillis = (System.nanoTime() - t0) / (1000L * 1000L);
      if (elapsedMillis >= profileThreshold)
        System.out.printf("%n%s: %d%n", toString(), elapsedMillis);
    }
  }

  //     /**

    return SampleElements.mapEntries(keys, values);
  }

  @Override
  public Set<Entry<K, V>> create(Object... elements) {
    Entry<K, V>[] entries = createArray(elements.length);
    System.arraycopy(elements, 0, entries, 0, elements.length);
    return createFromEntries(entries);
  }

  public abstract Set<Entry<K, V>> createFromEntries(Entry<K, V>[] entries);

  @Override