Major Description
if the incoming message like
<soap:envelope><soap:body><a1><a2>...<an></an>...</a2</a2></soap:body></soap:envelope>
"n" here could be very huge, then it will take long time(a 500k size message with only element tag but no real content will take minutes) for staxutils to parse this message. In some case, this kind of message with unreasonable inner element level should be considered as vulnerability, so we need introduce inner element level threshold property for staxutils, so that we get chance that if it reach the threshold, just throw exception and stop parsing, this way ensure release resource soon in case of vulnerability.
The default value of this property should be -1 which means no inner element limit, for backward compatible.