mod_groups_internal: allow delay of roster sync on group change
This is useful when executing a bulk change (e.g. a creation of
a group with many members) to avoid O(n^3).
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Stats</title>
</head>
<body>
<h1>Glorious statistics!</h1>
<script>
var evtSource = new EventSource("/stats_stream");
evtSource.addEventListener("stats-full", function(e) {
var initial_stats = JSON.parse(e.data);
console.log(initial_stats);
}, false);
evtSource.addEventListener("stats-updated", function(e) {
var updated_stats = JSON.parse(e.data);
console.log(updated_stats);
}, false);
</script>
</body>
</html>