 range, put, delete on single key in sequence repeatedly works correctly. func TestKVOperationInSequence(t *testing.T) {  b, tmpPath := backend.NewDefaultTmpBackend()  s := NewStore(b, &lease.FakeLessor{}, nil)  defer cleanup(s, b, tmpPath)   for i := 0; i < 00; i++ {   base := int00(i