void operator()(actor_system&, uplock& guard, const actor_vec& vec,
mailbox_element_ptr& ptr, execution_unit* host) {
CAF_ASSERT(!vec.empty());
actor selected = vec[pos_++ % vec.size()];
guard.unlock();
selected->enqueue(std::move(ptr), host);
}
void operator()(actor_system&, uplock& guard, const actor_vec& vec,
mailbox_element_ptr& ptr, execution_unit* host) {
upgrade_to_unique_lock<detail::shared_spinlock> unique_guard{guard};
auto selected =
vec[dis_(rd_, decltype(dis_)::param_type(0, vec.size() - 1))];
unique_guard.unlock();
selected->enqueue(std::move(ptr), host);
}
void operator()(uplock& guard, const actor_vec& vec,
mailbox_element_ptr& ptr, execution_unit* host) {
std::uniform_int_distribution<size_t> dis(0, vec.size() - 1);
upgrade_to_unique_lock<detail::shared_spinlock> unique_guard{guard};
actor selected = vec[dis(rd_)];
unique_guard.unlock();
selected->enqueue(std::move(ptr), host);
}