code: public static <T extends Chunkable> byte[] chunkFrom(T chunkable, int chunkLength,
                                                           int chunkNum) {
          int start = chunkNum * chunkLength;
          return bytesFrom(chunkable, start, chunkLength);
      }
docs: Retrieve a chunk of raw bytes. Chunks are created by slicing the array at even intervals.
  The final chunk may be shorter than the other chunks if it's been truncated.
  
  @param chunkLength   The length of each chunk
  @param chunkNum      The chunk at which to start, zero-indexed
  @return              The chunk (array of bytes)