code: private void pruneExpiredQueries()
      {
          if (expirationQueue.size() <= maxQueryHistory) {
              return;
          }
  
          int count = 0;
          // we're willing to keep full info for up to maxQueryHistory queries
          for (T query : expirationQueue) {
              if (expirationQueue.size() - count <= maxQueryHistory) {
                  break;
              }
              query.pruneInfo();
              count++;
          }
      }
docs: Prune extraneous info from old queries