ElapsedTimer: Measure amount of time with a monotonic clock.
https://sourceforge.net/p/acpl/code/ci/master/tree/acpl/Examples/ElapsedTimer/main.cpp
#include <iostream>
#include <thread>
#include <core/util/ElapsedTimer.hpp>
using namespace acpl;
using namespace std::chrono_literals;
int main() {
std::cout << "Start timer and wait for 2 seconds ...\n";
auto timer = ElapsedTimer::create();
std::this_thread::sleep_for(2s);
std::cout << timer.elapsed().count() << " seconds later\n";
return 0;
}