@Override
    public void reset() {
        if (markBuffer != null) {
            System.arraycopy(markBuffer, 0, tailBuffer, 0, tailSize);
            currentIndex = markIndex;
            bytesRead = markBytesRead;
        }
    }
{@inheritDoc} This implementation restores this stream's state to the
state when ''mark()'' was called the last time. If ''mark()'' has not
been called before, this method has no effect.
tika-core/src/main/java/org/apache/tika/io/TailStream.java