Issue with multipart file upload with CefURLRequest::Create

[SolidMercury]

When custom resource handler is used multipart file upload is not working. Quick debugging showed that UploadFileElementReader is not getting called and there is no file content being sent. But with default handler its is working fine. The custom resource handler is calling CefURLRequest::Create(request, client.get(), nullptr); in the ProcessRequest().

Just before the CefURLRequest::Create, checked the request objects's Postdata element vector. It does have 3 elements.
1. Byte type

------WebKitFormBoundaryHJMzwpTe5ThmqsIy
Content-Disposition: form-data; name="textline"


------WebKitFormBoundaryHJMzwpTe5ThmqsIy
Content-Disposition: form-data; name="datafile"; filename="test.reg"
Content-Type: application/octet-stream



2. File type: Contains path to selected file.

3. Byte type

------WebKitFormBoundaryHJMzwpTe5ThmqsIy--

But when the request is made, the above contents are not part of the request which has been verified from the fiddler as well as the debugger.
After debugging further it was found that the multi-part support is not implemented as per the code at https://bitbucket.org/chromiumembedded/ ... mpl.cc-333.

Am I missing something here or is it really not supported? If it is not, are there any workaround to get this working? Does concatenating multiple elements into one byte type element make this to work?