Support Optional Request Body & Optional Content Type

[jorgerangel-msft]

Consider the following spec : link

Here the request body and the content type header are optional. The content type header should only be added to the request if the request body is not empty. Currently, we generate invalid code that will always add the content type parameter:

if ("application/xml" != null)
{
    request.Headers.SetValue("Content-Type", "application/xml");
}

Instead, we should check if the request content is null, and if not, apply the content type:

if (content != null)
{
    request.Headers.SetValue("Content-Type", "application/xml");
    request.Content = content;
}