#include <iostream>

struct fiber
{
    fiber(auto &&f) { f(); }
};

void funcion() { std::cout << "1\n"; }

auto lambda = [] { std::cout << "2\n"; };

struct objeto
{
    void operator()() { std::cout << "3\n"; }
};

int main()
{
    fiber f1(funcion), f2(objeto{}), f3(lambda), f4([] { std::cout << "4\n"; });
}