@Override
    public XmlXOutput clear()
    {
        super.clear();

        return this;
    }
Optimized xml output. The string values are not escaped (its assumed are no xml control chars or that they've been
validated and xml-escaped on input).

@author David Yu
@created Aug 30, 2012
protostuff-xml/src/main/java/io/protostuff/XmlXOutput.java