protected HazelcastInstance ensureHazelcastInstance() {
        if (this.hazelcastInstance == null) {
            this.hazelcastInstance = createHazelcastInstance();
            this.implicitlyCreated = true;
        }
        return this.hazelcastInstance;
    }
Ensures that this implementation has a backing {@link HazelcastInstance}, and if not, implicitly creates one
via {@link #createHazelcastInstance()}.

@return the backing (potentially newly created) {@code HazelcastInstance}.
@see #createHazelcastInstance()
@see HazelcastInstance
support/hazelcast/src/main/java/org/apache/shiro/hazelcast/cache/HazelcastCacheManager.java