just rely on escape analysis

alloc/allocators.go

@@ -157,11 +157,10 @@ func Nil() Allocator {
 
 // Temporary wraps an Allocator, restoring it to its previous state when Reset is called.
 func Temporary(alloc Allocator) Allocator {
-	watermark := new(uintptr)
-	*watermark = Save(alloc)
+	watermark := Save(alloc)
 	return func(a Action, size, align uintptr, wm *uintptr) (unsafe.Pointer, error) {
 		if a == ActionReset {
-			Restore(alloc, *watermark)
+			Restore(alloc, watermark)
 			return nil, nil
 		}