public abstract C previous(C value);

  /**
   * Returns a signed value indicating how many nested invocations of {@link #next} (if positive) or
   * {@link #previous} (if negative) are needed to reach {@code end} starting from {@code start}.
   * For example, if {@code end = next(next(next(start)))}, then {@code distance(start, end) == 3}
   * and {@code distance(end, start) == -3}. As well, {@code distance(a, a)} is always zero.
   *

   *
   * @param numBytes the number of bytes in the byte array
   * @param expectedCount the expected number of roundtrippable permutations
   * @param start the starting bytes encoded as a long as big-endian
   * @param lim the limit of bytes to process encoded as a long as big-endian, or -1 to mean the max
   *     limit for numBytes
   */
  @GwtIncompatible // java.nio.charset.Charset

   * </pre>
   *
   * @param throwable the non-null {@code Throwable} to extract causes from
   * @return an unmodifiable list containing the cause chain starting with {@code throwable}
   * @throws IllegalArgumentException if there is a loop in the causal chain
   */
  public static List<Throwable> getCausalChain(Throwable throwable) {
    checkNotNull(throwable);

   * </pre>
   *
   * @param throwable the non-null {@code Throwable} to extract causes from
   * @return an unmodifiable list containing the cause chain starting with {@code throwable}
   * @throws IllegalArgumentException if there is a loop in the causal chain
   */
  public static List<Throwable> getCausalChain(Throwable throwable) {
    checkNotNull(throwable);

   * string of size {@code size}, and are in order. A position index may range from zero to {@code
   * size}, inclusive.
   *
   * @param start a user-supplied index identifying a starting position in an array, list or string
   * @param end a user-supplied index identifying an ending position in an array, list or string
   * @param size the size of that array, list or string

    assertTrue(Arrays.equals(reference, target));
    assertTrue(Arrays.equals(reference, target));

    Object[] expectedArray1 = expectModify ? reference : starting;
    Object[] expectedArray2 = expectModify ? target : starting;
    assertTrue(Arrays.equals(expectedArray1, array1));
    assertTrue(Arrays.equals(expectedArray2, array2));
  }

  public void testPrependZeroElements() {

    // as their length. These files are very small, so it's wasteful to allocate an 8KB buffer.
    int initialBufferSize = min(BUFFER_SIZE, max(128, Integer.highestOneBit(totalLen) * 2));
    // Starting with an 8k buffer, double the size of each successive buffer. Smaller buffers
    // quadruple in size until they reach 8k, to minimize the number of small reads for longer

  public abstract C previous(C value);

  /**
   * Returns a signed value indicating how many nested invocations of {@link #next} (if positive) or
   * {@link #previous} (if negative) are needed to reach {@code end} starting from {@code start}.
   * For example, if {@code end = next(next(next(start)))}, then {@code distance(start, end) == 3}
   * and {@code distance(end, start) == -3}. As well, {@code distance(a, a)} is always zero.
   *

    assertTrue(Arrays.equals(reference, target));
    assertTrue(Arrays.equals(reference, target));

    Object[] expectedArray1 = expectModify ? reference : starting;
    Object[] expectedArray2 = expectModify ? target : starting;
    assertTrue(Arrays.equals(expectedArray1, array1));
    assertTrue(Arrays.equals(expectedArray2, array2));
  }

  public void testPrependZeroElements() {

   */
  public int indexIn(CharSequence sequence) {
    return indexIn(sequence, 0);
  }

  /**
   * Returns the index of the first matching BMP character in a character sequence, starting from a
   * given position, or {@code -1} if no character matches after that position.
   *
   * <p>The default implementation iterates over the sequence in forward order, beginning at {@code