React-Native send multipart/form-data through HTTP

I have a react-native app that needs to send video/images to my server. I already know that normal posts work but when I attempt to send a formData object, it seems to never leave the phone. Here is my code.

// method = 'POST';
// body = new formData();
// body contains text data and image/video file
const post = (url, body, token, method) => {
  let xhr = new XMLHttpRequest();
  xhr.open(method, url);
  xhr.setRequestHeader('Authorization', 'Bearer' + token);
  xhr.setRequestHeader('Content-Type', 'multipart/form-data; boundary=---------------------------7692764ac82');
  xhr.send(body);
  console.log(xhr);
  return xhr.response;
}

body is a formData object that contains an image/video. In the object that xhr prints at the console log the _response contains "Binary FormData part needs a content-type header." But it seems I set it correctly right?

Please help, there are other similar questions but I have run out of ideas. I have also tried using fetch with no success.