private void warnAboutPrivateUseChar() throws SAXException {
        if (!alreadyWarnedAboutPrivateUseCharacters) {
            handler.warn("Document uses the Unicode Private Use Area(s), which should not be used in publicly exchanged documents. (Charmod C073)");
            alreadyWarnedAboutPrivateUseCharacters = true;
        }
    }
Filter carriage returns in the read buffer. CRLF becomes LF; CR becomes
LF.

@param moreData
           true iff more data might come from the same source
@see #readDataChunk
@see #readBuffer
@see #readBufferOverflow
src/nu/validator/gnu/xml/aelfred2/XmlParser.java