function updateWithConfig(obj, config) {
        if (config) {
            assertConfig(config)
              .whereParam("resourceName").isOptional().isString()
              .whereParam("dataService").isOptional().isInstanceOf(DataService)
              .whereParam("allowConcurrentSaves").isBoolean().isOptional()
              .whereParam("tag").isOptional()
              .applyAll(obj);
        }
        return obj;
    }
Returns a copy of this SaveOptions with the specified config options applied.
    @example
        var saveOptions = em1.saveOptions.using( {resourceName: "anotherResource" });
    
    @method using
    @param config {Configuration Object|} The object to apply to create a new SaveOptions.
    @param [config.allowConcurrentSaves] {Boolean} Whether multiple saves can be in-flight at the same time. The default is false.
    @param [config.resourceName] {String} Resource name to be used during the save - this defaults to "SaveChanges"
    @param [config.dataService] {DataService} The DataService to be used for this save.
    @param [config.tag] {Object} Free form value that will be sent to the server during the save. 
    @chainable