completed = function (page) {
            textures[page.metadata.pageFile] = page.texture;
            if (Object.keys(textures).length === data.page.length) {
                resource.bitmapFont = BitmapFont.install(data, textures, true);
                next();
            }
        }
Called after a resource is loaded.
@see PIXI.Loader.loaderMiddleware
@param this
@param {PIXI.LoaderResource} resource
@param {Function} next