private static int availableCapacity(Buffer buffer) {
    return buffer.capacity() - buffer.limit();
  }

  /**
   * Flips the buffer output buffer so we can start reading bytes from it. If we are starting to
   * drain because there was overflow, and there aren't actually any characters to drain, then the
   * overflow must be due to a small output buffer.
   */
  private void startDraining(boolean overflow) {

    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
    // streams. Buffers are retained in a deque so that there's no copying between buffers while

  private static long fingerprint(byte[] bytes, int length) {
    return HASH_FN.hashBytes(bytes, 0, length).asLong();
  }

  /**
   * Tests that the Java port of Fingerprint2011 provides the same results on buffers up to 800
   * bytes long as the original implementation in C++. See http://cl/106539598
   */
  public void testMultipleLengths() {
    int iterations = 800;
    byte[] buf = new byte[iterations * 4];

  private static long fingerprint(byte[] bytes, int length) {
    return HASH_FN.hashBytes(bytes, 0, length).asLong();
  }

  /**
   * Tests that the Java port of Fingerprint2011 provides the same results on buffers up to 800
   * bytes long as the original implementation in C++. See http://cl/106539598
   */
  public void testMultipleLengths() {
    int iterations = 800;
    byte[] buf = new byte[iterations * 4];

      to.append(buf);
      total += buf.remaining();
      Java8Compatibility.clear(buf);
    }
    return total;
  }

  // TODO(lukes): consider allowing callers to pass in a buffer to use, some callers would be able
  // to reuse buffers, others would be able to size them more appropriately than the constant
  // defaults

  /**
   * Copies all characters between the {@link Reader} and {@link StringBuilder} objects. Does not

         * InterruptibleChannel and JavaLangAccess.blockedOn(Thread, Interruptible), it isn't
         * predictable what work might be done. (e.g., close a file and flush buffers to disk). To
         * protect ourselves from this, we park ourselves and tell our interrupter that we did so.
         */
        if (state == PARKED || compareAndSet(state, PARKED)) {
          // Interrupting Cow Says:

   * should speed up for a while, to take advantage of these resources. This is important when the
   * rate is applied to networking (limiting bandwidth), where past underutilization typically
   * translates to "almost empty buffers", which can be filled immediately.
   *
   * On the other hand, past underutilization could mean that "the server responsible for handling
   * the request has become less ready for future requests", i.e. its caches become stale, and

    byte[] b = ByteStreams.toByteArray(in);
    assertThat(b).isEqualTo(new byte[0]);
  }

  public void testToByteArray_largeStream() throws IOException {
    // well, large enough to require multiple buffers
    byte[] expected = newPreFilledByteArray(10000000);
    InputStream in = new ByteArrayInputStream(expected);
    byte[] b = ByteStreams.toByteArray(in);
    assertThat(b).isEqualTo(expected);
  }

    byte[] b = ByteStreams.toByteArray(in);
    assertThat(b).isEqualTo(new byte[0]);
  }

  public void testToByteArray_largeStream() throws IOException {
    // well, large enough to require multiple buffers
    byte[] expected = newPreFilledByteArray(10000000);
    InputStream in = new ByteArrayInputStream(expected);
    byte[] b = ByteStreams.toByteArray(in);
    assertThat(b).isEqualTo(expected);
  }

    // requireNonNull accommodates Android's @RecentlyNullable annotation on ThreadLocal.get
    return requireNonNull(DEST_TL.get());
  }

  /**
   * A thread-local destination buffer to keep us from creating new buffers. The starting size is
   * 1024 characters. If we grow past this we don't put it back in the threadlocal, we just keep
   * going and grow as needed.
   */
  private static final ThreadLocal<char[]> DEST_TL =