* Cache.asMap().putIfAbsent} after loading has completed; if another value was associated with
   * {@code key} while the new value was loading then a removal notification will be sent for the
   * new value.
   *
   * <p>If the cache loader associated with this cache is known not to throw checked exceptions,
   * then prefer {@link #getUnchecked} over this method.
   *

   * is perpetually "flipped" (unencoded characters between position and limit).
   */
  private CharBuffer charBuffer;

  /**
   * byteBuffer holds encoded characters that have not yet been sent to the caller of the input
   * stream. When encoding it is "unflipped" (encoded bytes between 0 and position) and when
   * draining it is flipped (undrained bytes between position and limit).
   */

   * complete chunk are handled with {@link #processRemaining}.
   */
  protected abstract HashCode makeHash();

  // Process pent-up data in chunks
  private void munchIfFull() {
    if (buffer.remaining() < 8) {
      // buffer is full; not enough room for a primitive. We have at least one full chunk.
      munch();
    }
  }

   * Cache.asMap().putIfAbsent} after loading has completed; if another value was associated with
   * {@code key} while the new value was loading then a removal notification will be sent for the
   * new value.
   *
   * <p>If the cache loader associated with this cache is known not to throw checked exceptions,
   * then prefer {@link #getUnchecked} over this method.
   *