@GetMapping("/getFromGrpc")
    public String getFromGrpc() {
        return Optional.ofNullable(GrpcClientBuilder.buildExecutor())
                .map(Object::toString)
                .orElse("");
    }
get the shared thread pool from grpc.

@return the shared thread pool
shenyu-integrated-test/shenyu-integrated-test-combination/src/main/java/org/apache/shenyu/integrated/test/combination/controller/SharedThreadPoolController.java