code: synchronized void removeHandler(ServiceReference<?> serviceReference) {
          HandlerHolder holder = serviceReferenceMap.remove(serviceReference);
  
          if (holder != null) {
              for (String topic : holder.getDiscreteTopics()) {
                  removeTopicHandlerFromMap(topic, holder, discreteEventHandlers);
              }
              for (String topic : holder.getWildcardTopics()) {
                  removeTopicHandlerFromMap(topic, holder, wildcardEventHandlers);
              }
          }
  
          // Clear the cache since it's no longer up to date
          clearTopicDataCache();
      }
docs: Remove an <code>EventHandler</code> <code>ServiceReference</code> from
  our collection. Removing a handler reference will cause us to clear all
  references to it in our topic maps.
  
  @param serviceReference
  the <code>EventHandler</code> reference