use Time::HiRes qw( gettimeofday tv_interval );

);
$prom->declare(
    "notify_event_runtime",
    type => "histogram",
    help => "Number of seconds spent executing events by channel."

        my $start_time = [gettimeofday()];

        }

        };
        $prom->histogram_observe("notify_event_runtime", tv_interval($start_time), { channel => $channelName });