code: private void cleanup_event_filters() {
          Enumeration keys = event_callback_map.keys();
          while (keys.hasMoreElements()) {
              String name = (String) keys.nextElement();
              EventCallBackStruct callback_struct = event_callback_map.get(name);
              if (callback_struct.consumer instanceof NotifdEventConsumer) {
                  try {
                      EventChannelStruct ec_struct = channel_map.get(callback_struct.channel_name);
                      Filter filter = ec_struct.structuredProxyPushSupplier.get_filter(callback_struct.filter_id);
                      ec_struct.structuredProxyPushSupplier.remove_filter(callback_struct.filter_id);
                      filter.destroy();
                  } catch (FilterNotFound e) {
                      // Do nothing
                  }
              }
          }
      }
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