Merge pull request #400 from portsip/Use-find-to-instead-of-the-count - Replace set with unordered_set in BasicDomainMatcher and ExtendedDomainMatcher. - Use find() instead of count() for element existence checks in STL containers. - Optimize locking in DnsInterface::isSupported(). - Early return in ExtendedDomainMatcher::isMyDomain() when mDomainSuffixList is empty, preventing unnecessary domain case conversions.