chore: for backward compatibility (#4852)

Signed-off-by: kevin <wanjunfeng@gmail.com>

core/syncx/once.go

@@ -0,0 +1,9 @@
+package syncx
+
+import "sync"
+
+// Once returns a func that guarantees fn can only called once.
+// Deprecated: use sync.OnceFunc instead.
+func Once(fn func()) func() {
+	return sync.OnceFunc(fn)
+}