code: public void disconnectOnChange(@Observes final iOSVariantUpdateEvent iOSVariantUpdateEvent) {
          final iOSVariant variant = iOSVariantUpdateEvent.getiOSVariant();
          final String connectionKey = extractConnectionKey(variant);
          final ApnsClient client = apnsClientExpiringMap.remove(connectionKey);
          logger.debug("Removed client from cache for {}", variant.getVariantID());
          if (client != null) {
              tearDownApnsHttp2Connection(client);
          }
      }
docs: Receives iOS variant change event to remove client from the cache and also tear down the connection.
  @param iOSVariantUpdateEvent event fired when updating the variant