Disable DF on direct outbound by default

outbound/direct.go

@@ -35,6 +35,7 @@ type Direct struct {
 }
 
 func NewDirect(router adapter.Router, logger log.ContextLogger, tag string, options option.DirectOutboundOptions) (*Direct, error) {
+	options.UDPFragmentDefault = true
 	outbound := &Direct{
 		myOutboundAdapter: myOutboundAdapter{
 			protocol: C.TypeDirect,