@Override
    public String toString() {
        return "RequestHandlerResult["
                + "code="
                + code
                + ", reason='"
                + reason
                + '\''
                + ", response="
                + ProtoFormatter.toLogString(response)
                + ", notifications="
                + notifications
                + ']';
    }
@param code          The status code of the response.
@param reason        The reason of the response.
@param response      The response to be sent to the requester.
@param notifications The notifications to be sent to users.
@author James Chen
turms-service/src/main/java/im/turms/service/access/servicerequest/dto/RequestHandlerResult.java