/**
   * This is invoked for the last bytes of the input, which are not enough to fill a whole chunk.
   * The passed {@code ByteBuffer} is guaranteed to be non-empty.
   *
   * <p>This implementation simply pads with zeros and delegates to {@link #process(ByteBuffer)}.
   */
  protected void processRemaining(ByteBuffer bb) {
    Java8Compatibility.position(bb, bb.limit()); // move at the end