EPOLL_CTL_MOD
result = epoll_ctl(epollfd, EPOLL_CTL_MOD, fd, &event);
if (op == EPOLL_CTL_MOD)
case EPOLL_CTL_MOD:
error = epoll_ctl(epollfd, EPOLL_CTL_MOD, fd, &ev);
ret = epoll_ctl(efd, EPOLL_CTL_MOD, fd, &ev);
epoll_ctl(ctx->efd[0], EPOLL_CTL_MOD, ctx->sfd[0], &e);