docs: async function httpsRequest (opts, formData) {
    return new Promise
    ((resolve, reject) => {
      let req = https.request (opts, (res) => {
        let data = '';
        res.on('data', (chunk) => { data += chunk; });
        res.on('end', () => {
  	resolve ([res, data]);
        });
      });
      if (formData)
        req.write (formData);
      req.end();
    });
  }