@Override
    public void call(ConfigurationRequest request,
                     StreamObserver<ConfigurationResponse> responseObserver) {
        ConfigurationResponse response;
        String uuid = request.getUuid();
        switch (this.dataFlag.get()) {
            case 1:
                response = ConfigurationResponse
                    .newBuilder().setUuid(UUID.randomUUID().toString())
                    .addConfigTable(Config
                                        .newBuilder()
                                        .setName("test-module.grpc.testKey")
                                        .setValue("300")
                                        .build()).build();
                responseObserver.onNext(response);
                break;
            case 2:
                response = ConfigurationResponse.newBuilder().setUuid(uuid).build();
                responseObserver.onNext(response);
                break;
            case 3:
                response = ConfigurationResponse
                    .newBuilder().setUuid(UUID.randomUUID().toString())
                    .addConfigTable(Config
                                        .newBuilder()
                                        .setName("test-module.grpc.testKey")
                                        .build()).build();
                responseObserver.onNext(response);
                break;
            default:
                response = ConfigurationResponse
                    .newBuilder().setUuid(UUID.randomUUID().toString())
                    .addConfigTable(Config
                                        .newBuilder()
                                        .setName("test-module.grpc.testKey")
                                        .setValue("100")
                                        .build()).build();
                responseObserver.onNext(response);
        }
        responseObserver.onCompleted();
    }
@param dataFlag 0:init, 1:change, 2:no change, 3:delete
oap-server/server-configuration/grpc-configuration-sync/src/test/java/org/apache/skywalking/oap/server/configuration/grpc/MockGRPCConfigService.java