Setting user-agent on iOS HTMLViewer

Is anyone aware of a declare enabling the user-agent of the iOS HTMLViewer to be set to a value other than mobile Safari? While supported natively in desktop apps, it appears the iOS HTMLViewer does not support it.

Swift example:

let userAgent = "My Cool User Agent"
if let url = NSURL(string: "http://whatsmyuseragent.com/") {
   let request = NSMutableURLRequest(URL: url)
   request.setValue(userAgent, forHTTPHeaderField: "User-Agent")
   var response:NSURLResponse? = nil;
   var error:NSError? = nil;
   if let data = NSURLConnection.sendSynchronousRequest(request, returningResponse: &response, error: &error) {
      // do something with your data
   }
 }