How can I upload attachments (e.g. images) using the media WP-API endpoint?

Here's my code using request:

var request = require('request');
    var fs = require('fs');

    var formData = {
          file: fs.createReadStream('path_and_filename')
    };

    request.post({url:media_endpoint_url, formData: formData}, 
        function optionalCallback(err, httpResponse, body) {    
          if (err) {
            return console.error('upload failed:', err);
          }
          console.log('Upload successful!  Server responded with:', body);
        })
    .auth('username','password',true);