docs: protected PollItem filter(final Object socketOrChannel, int events)
      {
          if (socketOrChannel == null) {
              return null;
          }
          CompositePollItem item = items.get(socketOrChannel);
          if (item == null) {
              return null;
          }
          PollItem pollItem = item.item();
          if (pollItem == null) {
              return null;
          }
          if (pollItem.hasEvent(events)) {
              return pollItem;
          }
          return null;
      }