public override void WriteStartElement( string prefix, string localName, string ns) {
Debug.Assert( localName != null && localName.Length > 0 );
Debug.Assert( prefix != null );
bufBytes[bufPos++] = (byte) '<';
if ( prefix != null && prefix.Length != 0 ) {
RawText( prefix );
bufBytes[this.bufPos++] = (byte) ':';
}
RawText( localName );
attrEndPos = bufPos;
}