for (auto build2 : dependents)
            if (build2->drvPath == step->drvPath) { build = build2; break; }

        for (auto build2 : dependents) {
            if (build2->drvPath == step->drvPath) {
              build = build2;
              {
                  auto notificationSenderQueue_(notificationSenderQueue.lock());
                  notificationSenderQueue_->push(NotificationItem{NotificationItem::Type::Started, build->id});
              }
              notificationSenderWakeup.notify_one();
            }
        }

                notificationSenderQueue_->push(NotificationItem(id, std::vector<BuildID>()));

                notificationSenderQueue_->push(NotificationItem{NotificationItem::Type::Finished, id});

            notificationSenderQueue_->push(NotificationItem(build->id, dependentIDs));

            notificationSenderQueue_->push(NotificationItem{NotificationItem::Type::Finished, build->id, dependentIDs});

            printMsg(lvlChatty, format("sending notification about build %1%") % item.first);

            printMsg(lvlChatty, format("sending notification about build %1%") % item.id);

                Strings argv({"hydra-notify", "build", std::to_string(item.first)});
                for (auto id : item.second)

                Strings argv({"hydra-notify", item.type == NotificationItem::Type::Started ? "build-started" : "build-finished", std::to_string(item.id)});
                for (auto id : item.dependentIds)

                    % res % item.first);

                    % res % item.id);

    typedef std::pair<BuildID, std::vector<BuildID>> NotificationItem;

    struct NotificationItem
    {
        enum class Type : char {
           Started,
           Finished
        };
        Type type;
        BuildID id;
        std::vector<BuildID> dependentIds;
    };

    notifyBuildStarted

sub notifyBuildStarted {
    my ($plugins, $build) = @_;
    foreach my $plugin (@{$plugins}) {
        eval {
            $plugin->buildStarted($build);
        };
        if ($@) {
            print STDERR "$plugin->buildStarted: $@\n":
        }
    }
}

# Called when build $build has started.
sub buildStarted {
    my ($self, $build) = @_;
}

my $cmd = shift @ARGV or die "Syntax: hydra-notify build BUILD-ID [BUILD-IDs...]\n";

my $cmd = shift @ARGV or die "Syntax: hydra-notify CMD BUILD-ID [BUILD-IDs...]\n";

if ($cmd eq "build") {
    my $buildId = shift @ARGV or die;
    my $build = $db->resultset('Builds')->find($buildId)
        or die "build $buildId does not exist\n";

my $buildId = shift @ARGV or die;
my $build = $db->resultset('Builds')->find($buildId)
    or die "build $buildId does not exist\n";
if ($cmd eq "build-finished") {

} elsif ($cmd eq "build-started") {
    notifyBuildStarted(\@plugins, $build);