function _httpHead( wpreq ) {
	const url = wpreq.toString();
	const config = _setHeaders( _auth( {
		method: 'HEAD',
	}, wpreq._options, true ), wpreq._options );

	return fetch( url, config )
		.then( response => getHeaders( response ) );
}
@method head
@async
@param {WPRequest} wpreq A WPRequest query object
@returns {Promise} A promise to the header results of the HTTP request