kubernetes/vendor/go.etcd.io/etcd/pkg/v3/ioutil/util.go

// WriteAndSyncFile behaves just like ioutil.WriteFile in the standard library,
// but calls Sync before closing the file. WriteAndSyncFile guarantees the data
// is synced if there is no error returned.
func WriteAndSyncFile(filename string, data []byte, perm os.FileMode) error { … }