update:Use the official sync.OnceFunc (#4840)

core/syncx/once_test.go

@@ -1,33 +0,0 @@
-package syncx
-
-import (
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-)
-
-func TestOnce(t *testing.T) {
-	var v int
-	add := Once(func() {
-		v++
-	})
-
-	for i := 0; i < 5; i++ {
-		add()
-	}
-
-	assert.Equal(t, 1, v)
-}
-
-func BenchmarkOnce(b *testing.B) {
-	var v int
-	add := Once(func() {
-		v++
-	})
-
-	b.ResetTimer()
-	for i := 0; i < b.N; i++ {
-		add()
-	}
-	assert.Equal(b, 1, v)
-}