nsIRDFXMLSinkObserver* obs = (nsIRDFXMLSinkObserver*) mObservers[i]; obs->OnBeginLoad(this);
nsCOMPtr<nsIRDFXMLSinkObserver> obs = mObservers[i];  if (obs) { obs->OnBeginLoad(this); }
RDFXMLDataSourceImpl::BeginLoad(void){    mIsLoading = PR_TRUE;    for (PRInt32 i = mObservers.Count() - 1; i >= 0; --i) {        nsIRDFXMLSinkObserver* obs = (nsIRDFXMLSinkObserver*) mObservers[i];        obs->OnBeginLoad(this);    }    return NS_OK;}