Migration: go1.21

component/dialer/mark_nonlinux.go

@@ -9,13 +9,9 @@ import (
 	"github.com/Dreamacro/clash/log"
 )
 
-var printMarkWarnOnce sync.Once
-
-func printMarkWarn() {
-	printMarkWarnOnce.Do(func() {
-		log.Warnln("Routing mark on socket is not supported on current platform")
-	})
-}
+var printMarkWarn = sync.OnceFunc(func() {
+	log.Warnln("Routing mark on socket is not supported on current platform")
+})
 
 func bindMarkToDialer(mark int, dialer *net.Dialer, _ string, _ net.IP) {
 	printMarkWarn()