Report SumStat$epoch_result with no observations

Hey guys,
I've written this small Zeek script to count and print the number of ICMP requests seen every specific time interval. Unfortunately, it does not report the value if there are no observations in that time interval... Any suggestion on how I could make it so it still reports 0 if there are no observations?

Best regards,

@load base/frameworks/sumstats


export {
    const icmp_request_epoch_interval = 5secs &redef;

event zeek_init()
    local icmp_request_r = SumStats::Reducer($stream="metric.icmp.request", $apply=set(SumStats::SUM));
    SumStats::create([$name = "metric.icmp.request.count",
                      $reducers = set(icmp_request_r),
                      $epoch = icmp_request_epoch_interval,
                      $epoch_result(s: time, key: SumStats::Key, result: SumStats::Result) =
                          print(fmt("Found %d icmp requests in the last interval", double_to_count(result["metric.icmp.request"]$sum)));

event icmp_echo_request(c: connection, info: icmp_info, id: count, seq: count, payload: string)
    SumStats::observe("metric.icmp.request", SumStats::Key(), SumStats::Observation($num=1));