/* Various stats. */
    std::atomic<int> nrQueueWakeups;

    void dumpStatus();

    nrQueueWakeups = 0;

    receiver dumpStatus(*conn, "dump_status");

        nrQueueWakeups++;

        if (dumpStatus.get())
            State::dumpStatus();

void State::dumpStatus()
{
    {
        auto builds_(builds.lock());
        printMsg(lvlError, format("%1% queued builds") % builds_->size());
    }
    {
        auto steps_(steps.lock());
        for (auto i = steps_->begin(); i != steps_->end(); )
            if (i->second.lock()) ++i; else i = steps_->erase(i);
        printMsg(lvlError, format("%1% pending/active build steps") % steps_->size());
    }
    {
        auto runnable_(runnable.lock());
        for (auto i = runnable_->begin(); i != runnable_->end(); )
            if (i->lock()) ++i; else i = runnable_->erase(i);
        printMsg(lvlError, format("%1% runnable build steps") % runnable_->size());
    }
    printMsg(lvlError, format("%1% times woken up to check the queue") % nrQueueWakeups);
    {
        auto machines_(machines.lock());
        for (auto & m : *machines_) {
            auto currentJobs_(m->currentJobs.lock());
            printMsg(lvlError, format("machine %1%: %2%/%3% active")
                % m->sshName % *currentJobs_ % m->maxJobs);
        }
    }
}

        parseCmdLine(argc, argv, [&](Strings::iterator & arg, const Strings::iterator & end) {
            return false;
        });