@Override
    public void mark(int readlimit) {
        super.mark(readlimit);
        mark = position;
    }
This relies on {@link IOUtils#skip(InputStream, long, byte[])} to ensure
that the alleged bytes skipped were actually skipped.

@param ln the number of bytes to skip
@return the number of bytes skipped
@throws IOException if the number of bytes requested to be skipped does not match the
number of bytes skipped or if there's an IOException during the read.
tika-core/src/main/java/org/apache/tika/io/TikaInputStream.java