code: function(object){
      var target = this.value();
      if(!object || !target || !target.isData || !object.isData){ return void 0; }
      target._cid || (target._cid = target.cid);
      object._cid || (object._cid = object.cid);
      target.cid = object.cid;
      this.tracking = object;
    }
docs: When we receive a new model to set in our cache, unbind the tracker from the previous cache object, sync the objects' cids so helpers think they are the same object, save a referance to the object we are tracking, and re-bind our onModify hook.