public static <T> Collection<T> doSynchronousClusterTask(ClusterTask<T> task, boolean includeLocalMember) {
        return cacheFactoryStrategy.doSynchronousClusterTask(task, includeLocalMember);
    }
Invokes a task on other cluster members synchronously and returns the result as a Collection
(method will not return until the task has been executed on each cluster member).
The task will not be executed on the local cluster member. If clustering is not enabled,
this method will return an empty collection.

@param task               the ClusterTask object to be invoked on all other cluster members.
@param includeLocalMember true to run the task on the local member, false otherwise
@param <T> the return type of the cluster task
@return collection with the result of the execution.
xmppserver/src/main/java/org/jivesoftware/util/cache/CacheFactory.java