code: public MappedBytes map(int offset, int size, FileChannel.MapMode mode) {
      MappedByteBuffer mappedByteBuffer = mapFile(randomAccessFile, offset, size, mode);
      return new MappedBytes(file, randomAccessFile, mappedByteBuffer, mode);
    }
docs: Maps a portion of the randomAccessFile into memory and returns a {@link UnsafeMappedBytes} instance.
  
  @param offset The offset from which to map the randomAccessFile into memory.
  @param size   The count of the bytes to map into memory.
  @param mode   The mode in which to map the randomAccessFile into memory.
  @return The mapped bytes.
  @throws IllegalArgumentException If {@code count} is greater than the maximum allowed
  {@link java.nio.MappedByteBuffer} count: {@link Integer#MAX_VALUE}