public static void fireMarkedAsSeniorClusterMember() {
        try {
            Log.info("Firing marked as senior event");
            events.put(new Event(EventType.marked_senior_cluster_member, null));
        } catch (InterruptedException e) {
            // Should never happen
        }
    }
Triggers event indicating that this JVM is now the senior cluster member. This
could either happen when initially joining the cluster or when the senior cluster
member node left the cluster and this JVM was marked as the new senior cluster member.
<p>
Moreover, in the case of a "split brain" scenario (ie. separated cluster islands) each
island will have its own senior cluster member. However, when the islands meet again there
could only be one senior cluster member so one of the senior cluster members will stop playing
that role. When that happens the JVM no longer playing that role will receive the
{@link #fireLeftCluster()} and {@link #fireJoinedCluster(boolean)} events.</p>
<p>
This event will be triggered in another thread. This will avoid potential deadlocks
in Coherence.</p>
xmppserver/src/main/java/org/jivesoftware/openfire/cluster/ClusterManager.java