lockres = pthread_mutex_lock(&handler->sockets_mutex);
assert(lockres == 0);
assert(handler->pollfds[i - 1].fd == pollfds[i].fd); // Only we change fd order!
lockres = pthread_mutex_lock(&handler->sockets_mutex);
assert(lockres == 0);
assert(handler->pollfds[i - 1].fd == pollfds[i].fd); // Only we change fd order!