@Override
  public void close(String reason, Throwable optionalCause) {
    close(reason, optionalCause, false, false, false);
  }
Close the distributed system, cache servers, and gateways. Clears the rootRegions and
partitionedRegions map. Marks the cache as closed.

@see SystemFailure#emergencyClose()
geode-core/src/main/java/org/apache/geode/internal/cache/GemFireCacheImpl.java