code: protected boolean rawSkip(long bytes, boolean toNewSource) throws IOException {
  
      boolean result = seekOrSkip(bytes, toNewSource);
      setRawOffset(getRawOffset() + bytes);
  
      // Check validity
      if (rawBlockOffset > 0 && rawBlockOffset < metaDataBlockSize) {
        throw new IOException("Cannot jump into the middle of a MetaDataBlock. MetaDataBlockSize = "
            + metaDataBlockSize + " and we are at " + rawBlockOffset);
      }
      return result;
    }
docs: Skip some bytes from the raw InputStream.
  @param  toNewSource - only useful when seekableIn is not null.
  @return when toNewSource is true, return whether we seeked to a new source.
  otherwise return true.