Add scheduleIn(std::uint64_t ns, emper::io::Future::Callback fun)
Possible implementation
void scheduleIn(std::uint64_t ns, emper::io::Future::Callback fun) {
emper::io::AlarmFuture::Timespec ts = {.tv_sec = 0, .tv_nsec = ns};
emper::io::AlarmFuture alarmFuture(ts);
alarmFuture.setCallback(fun);
alarmFuture.submit();
}