docs: function(smooth) {
  
      var that = {};
      var window = [];
      var lastDelta = 0;
  
      that.adjust = function(rtt, delta) {
          if (window.length >= MAX_WINDOW_SIZE) {
              window.shift();
          }
          window.push({rtt: rtt, delta: delta});
          var minRTT = 99999999999999999999;
          var minIndex = -1;
          for (var i = 0; i < window.length; i++) {
              if (window[i].rtt < minRTT) {
                  minRTT = window[i].rtt;
                  minIndex = i;
              }
          }
          // low pass filter with exponential moving average
          lastDelta = Math.round(smooth * window[minIndex].delta +
                                 (1 - smooth) * lastDelta);
          return lastDelta;
      };
  
  
      return that;
  }