689ba36e92
The WrapUDPConn constructor returns nil when either arg is nil, so c.stats is always non-nil in all udpConn methods. Remove 8 redundant nil guards that were inconsistent with packetConn (which already skipped them). Add 65 unit tests across plugin, stats, and wrapper packages covering nil safety, race conditions, double-close, event marshaling, and reset-traffic semantics. Replace magic numbers in tests with named Kind constants.