public final synchronized void mark(int readLimit) {
        markPos = pointer;
        src.mark(readLimit);
    }
Forwards the request to the real <code>InputStream</code>.
We use {@link SeekableStream#markPos}
plugins/svg-plugin/batik-codec-fix/src/main/java/org/apache/batik/ext/awt/image/codec/util/ForwardSeekableStream.java