client/util.go
func IsKeyNotFound(err error) bool {
	if cErr, ok := err.(Error); ok {
		return cErr.Code == ErrorCodeKeyNotFound
	}
	return false
}
func IsKeyNotFound(err error) bool {
	if cErr, ok := err.(Error); ok {
		return cErr.Code == ErrorCodeKeyNotFound
	}
	return false
}
// IsKeyNotFound returns true if the error code is ErrorCodeKeyNotFound.