Using node and restler for multipart form-data POST
I am able to upload a file using restler.file in the data section with no problem. I am now trying to write a very short CSV data string, which I am not able to find documentation for the data function, but reading the code I thought I had it correct:
restler.post("http://posttestserver.com/post.php", {
    multipart: true,
    data: {
            "upload": restler.data("people.csv", "text/csv", '384;213;Status Update'),
            "returnURL": ""
    }
}).on("complete", function(data) {
     console.log(data);
});

Unfortunately this just hangs and will time out.  I tried adding EOF and other things to the 3rd arg but I know I am missing something.  The data string I have above is the exact same contents as the file that works when I use restler.file.  I would rather not have to write out a CSV file if I don't have to before POSTing it.

I got a note from the maintainer that the restler.data function was expecting a file as well, so I was not sure where to go with that.  I took a slightly different tact but achieved the result I was aiming for.  See my answer below if curious.

There was a problem with older restler code where a restler.data call as you did in your example would not properly submit the request. Anyway now a year after your original post this has been fixed in https://github.com/danwrong/restler/pull/172 It works fine for me now.

EDIT ----
As per @Joni's comment to the question above, this problem seems to have been rectified after a fix was submitted via pull request.
Original Answer (from OP) ----
From the research on restler (and corresponding with the maintainer) it doesn't look like restler can do what I wanted.  Note: Someone has committed some code that would allow a file part in the form of a stream, but it hasn't been accepted into the branch and I don't have enough experience with streams.
I solved the problem going back to basics.  I read the RFC for multipart (http://www.ietf.org/rfc/rfc2388.txt) and found there are only a few rules to be aware of in constructing the body, mostly some extra \r\n's and '--' in the right places.
I decided to simply format the raw POST body and send it through the basic node http client.
This worked:
var http = require('http');

postBody = new Buffer(
    '------WebKitFormBoundaryebFz3Q3NHxk7g4qY' + "\r\n" +
    'Content-Disposition: form-data; name="upload"; filename="filename.csv"' + "\r\n" +
    'Content-Type: text/csv' + "\r\n" +
    '\r\n' +
    'comma,separated,values' + "\r\n" +
    '------WebKitFormBoundaryebFz3Q3NHxk7g4qY' + "\r\n" +
    'Content-Disposition: form-data; name="returnUrl"' + "\r\n" + 
    '\r\n' +
    'http://return.url/' + "\r\n" +
    '------WebKitFormBoundaryebFz3Q3NHxk7g4qY--'
    );

var headers = {
  "Content-Type": "multipart/form-data; boundary=----WebKitFormBoundaryebFz3Q3NHxk7g4qY",
  "Content-Length": postBody.length
};

//These are the post options
var options = {
  hostname: 'myhost.com',
  port: 80,
  path: '/myPost',
  method: 'POST',
  headers: headers
};

// so we can see that things look right
console.log("postBody:\n" + postBody);
console.log("postBody.length:\n" + postBody.length);

var responseBody = '';

// set up the request and the callbacks to handle the response data
var request = http.request(options, function(response) {
    // when we receive data, store it in a string
    response.on('data', function (chunk) {
        responseBody += chunk;
    });
    // at end the response, run a function to do something with the response data
    response.on('end',function() {
        console.log(responseBody);
    });
});

// basic error function
request.on('error', function(e) {
  console.log('problem with request: ' + e.message);
});

// write our post body to the request
request.write(postBody);
// end the request
request.end();

I hope this helps people doing multipart/form-data.
