code: function movePropsToBackingStore(instance) {
  
          var bs = getBackingStore(instance);
          var proto = Object.getPrototypeOf(instance);
          var stype = proto.entityType || proto.complexType;
          stype.getProperties().forEach(function(prop) {
              var propName = prop.name;
              if (!instance.hasOwnProperty(propName)) return;
              // pulls off the value, removes the instance property and then rewrites it via ES5 accessor
              var value = instance[propName];
              delete instance[propName];
              instance[propName] = value;
          });
          return bs;
      }
docs: 'movePropsToBackingStore' called when an instance is first created via materialization or createEntity. this method cannot be called while a 'defineProperty' accessor is executing because of IE bug mentioned in 'startTracking'.