return (Collector) ONLY_ELEMENT;
  }

  /**
   * This atrocity is here to let us report several of the elements in the stream if there were more
   * than one, not just two.
   */
  private static final class ToOptionalState {
    static final int MAX_EXTRAS = 4;

    @CheckForNull Object element;
    List<Object> extras;

    ToOptionalState() {
      element = null;

But you should first read the **Tutorial - User Guide** (what you are reading right now).

    }
  }

  /**
   * Moves a file from one path to another. This method can rename a file and/or move it to a
   * different directory. In either case {@code to} must be the target path for the file itself; not
   * just the new name for the file or the path to the new parent directory.
   *
   * <p><b>{@link java.nio.file.Path} equivalent:</b> {@link java.nio.file.Files#move}.
   *
   * @param from the source file

        .putShort((short) 0x0100)
        .putShort((short) 0x0000)
        .putShort((short) 0x0000);
    assertEquals(hashCode, hasher.hash().asLong());
  }

  public void testHashFloatIsStable() {
    // Just a spot check.  Better than nothing.
    Hasher hasher = HASH_FN.newHasher();
    hasher.putFloat(0x01000101f).putFloat(0f);
    assertEquals(0x49f9d18ee8ae1b28L, hasher.hash().asLong());

    hasher = HASH_FN.newHasher();

   * process it; all should produce the same answer, the only difference should be the number of
   * process()/processRemaining() invocations, due to alignment.
   */
  @AndroidIncompatible // slow. TODO(cpovirk): Maybe just reduce iterations under Android.
  public void testExhaustive() throws Exception {
    Random random = new Random(0); // will iteratively make more debuggable, each time it breaks

      }
    }

    // Test _all_ allowed characters (including surrogate values).
    for (char ch = 0x20; ch <= 0xFFFD; ch++) {
      // There are a small number of cases to consider, so just do it manually.
      if (ch == '&') {
        assertEscaping(xmlEscaper, "&amp;", ch);
      } else if (ch == '<') {
        assertEscaping(xmlEscaper, "&lt;", ch);
      } else if (ch == '>') {

  /**
   * Returns an immutable array containing the given values, in order.
   *
   * <p>The array {@code rest} must not be longer than {@code Integer.MAX_VALUE - 1}.
   */
  // Use (first, rest) so that `of(someIntArray)` won't compile (they should use copyOf), which is
  // okay since we have to copy the just-created array anyway.
  public static ImmutableIntArray of(int first, int... rest) {
    checkArgument(

    // 150 milliseconds. so in a perfect world the timing would be 353-150=203ms, but since either
    // of our sleep calls can be arbitrarily delayed we should just assert that there is a time
    // recorded.
    assertThat(startupTimes.get(b)).isNotNull();
  }

  public void testServiceStartStop() {
    Service a = new NoOpService();
    Service b = new NoOpService();

  }

  // Static factories

  /**
   * Returns an ordering based on an <i>existing</i> comparator instance. Note that it is
   * unnecessary to create a <i>new</i> anonymous inner class implementing {@code Comparator} just
   * to pass it in here. Instead, simply subclass {@code Ordering} and implement its {@code compare}
   * method directly.
   *
   * <p>The returned object is serializable if {@code comparator} is serializable.
   *

                        // delete the local copy so the old details aren't used.
                        if (file.exists()) {
                            if (!file.delete()) {
                                // sleep for 10ms just in case this is windows holding a file lock
                                try {
                                    Thread.sleep(10);
                                } catch (InterruptedException ie) {