public Set getResults() {
      synchronized (results) {
        logger.debug("{} shutdownAll returning {}", this,
            results);
        return new HashSet(results);
      }
    }
If response arrives, we will save into results and keep wait for member's departure. If the
member is departed before sent response, no wait for its response
geode-core/src/main/java/org/apache/geode/internal/admin/remote/ShutdownAllRequest.java