Custom google storage API header on node.js

I am using googleapis.auth.JWT

for authentication and request

multi-page upload to upload JSON files to google storage, it works as expected.

Here is the code:

  var data = JSON.stringify(json);
  var metadata = {
      name: "name"
      contentLanguage: "en",
      acl: [...]
    };

  authClient.authorize(function(err, tokens) {
      if (err) {...}
      request.post({
        'url': 'https://....',
        'qs': {
          'uploadType': 'multipart'
        },  
        'headers' : { 
          'Authorization': 'Bearer ' + tokens.access_token
        },  
        'multipart':  [{  
          'Content-Type': 'application/json; charset=UTF-8',
          'body': JSON.stringify(metadata)
        },{ 
          'Content-Type': 'application/json',
          'body': data
        }]
      }, done);      
    });
  });
}

      

        
        
        
      

    

According to google here , if I want to enable custom headers, I need to add it as "x-goog-meta-mycustomheader"

When I change my above metadata object to this:

 var metadata = {
      name: "name"
      contentLanguage: "en",
      "x-goog-meta-something": "completely different",
      acl: [...]
  };

      

        
        
        
      

    

It has no effect.

How do I add custom headers when uploading an item to google storage?

EDIT :

Note that this is a multipart load that uses the body of the first part as the metadata of the second part (which is the actual part). Details here

In particular:

If you have metadata that you want to send along with the data being loaded, you can make one request to multipart / related. As with simple media-only queries, this is a good choice if the data you are sending is small enough to download completely if the connection fails.

Part of the metadata: must come first, and the Content-Type must match one of the accepted metadata formats.

Media part: must be the second, and the Content-Type must match one of the ways allowed for MIME types.

This is why I use metadata as the title section, I have also tried all other combinations like putting "x-goog-meta-something" in all other places