code: function(evts, key) {
        var saw1 = false, saw2 = false;
        for (var i = 0; i < evts.length; i++) {
          if (typeof c1State !== "undefined" && evts[i][key] == c1State[key]) {
            saw1 = true;
          }
          if (typeof c2State !== "undefined" && evts[i][key] == c2State[key]) {
            saw2 = true;
          }
        }
        return saw1 && saw2;
      }
docs: Checks if we see both users for a set of events