*/
    interface LexicographicalComparator extends Comparator<byte[]> {
      /** Returns whether this implementation is available for use on the current platform. */
      boolean isFunctional();
    }

    static final String UNSAFE_COMPARATOR_NAME =
        LexicographicalComparatorHolder.class.getName() + "$UnsafeComparator";

    assertThat(UnsignedBytes.join(",", (byte) 128, (byte) -1)).isEqualTo("128,255");
  }

  private static boolean unsafeComparatorAvailable() {
    return UnsafeComparator.INSTANCE.isFunctional();
  }

  public void testLexicographicalComparatorChoice() {
    Comparator<byte[]> defaultComparator = UnsignedBytes.lexicographicalComparator();
    assertThat(defaultComparator).isNotNull();

    assertThat(UnsignedBytes.join(",", (byte) 128, (byte) -1)).isEqualTo("128,255");
  }

  private static boolean unsafeComparatorAvailable() {
    return UnsafeComparator.INSTANCE.isFunctional();
  }

  public void testLexicographicalComparatorChoice() {
    Comparator<byte[]> defaultComparator = UnsignedBytes.lexicographicalComparator();
    assertThat(defaultComparator).isNotNull();