IDEA-129331 False positive for possible NPE
contract inference: honor delegate notnullness
XmlElementStorage — don't try to load data from stream provider if component roaming is disabled
FeatureUsageTracker — disable roaming
XmlElementStorage — don't try to load data from stream provider using any roaming type, use known if possible
cleanup, add testLoadFromStreamProvider
cleanup — exception is not thrown
cleanup
delete file if state is empty
simplify — don't wrap into document, use element directly