function WritableStreamDefaultControllerGetBackpressure(controller) {
		        const desiredSize = WritableStreamDefaultControllerGetDesiredSize(controller);
		        return desiredSize <= 0;
		    }
Fetch function

@param   {string | URL | import('./request').default} url - Absolute url or Request instance
@param   {*} [options_] - Fetch options
@return  {Promise<import('./response').default>}