chore(tun): not linux or not darwin tagged files

internal/tun/tun.go

@@ -1,13 +1,7 @@
 package tun
 
-import "golang.org/x/sys/unix"
-
-type Tun struct {
-	mknod func(path string, mode uint32, dev int) (err error)
-}
+type Tun struct{}
 
 func New() *Tun {
-	return &Tun{
-		mknod: unix.Mknod,
-	}
+	return &Tun{}
 }