this.bufferSize = bufferSize;
    this.chunkSize = chunkSize;
  }

  /** Processes the available bytes of the buffer (at most {@code chunk} bytes). */
  protected abstract void process(ByteBuffer bb);

  /**
   * 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.
   *