Different Type of Static Variable

struct Foo {
  int Add(int x) {
    static int a = rand() % 5;
    return a += x;
  }
};

struct Foo {
  static inline int a = rand() % 5;

  int Add(int x) {
    return a += x;
  }
};

* The benchmark is run under AMD Ryzen 9.

* For the full benchmark code, please refer here.