Allows you to specify additional HTTP headers.
First available in version 3.0 build 2039.
headers - HTTP headers separated by newlines. The last header must also have a trailing newline.
No output parameters.
When this method is called synchronously, a return object containing the output parameters is returned to the caller immediately.
See RFC 2068 (Hypertext Transfer Protocol - HTTP/1.1) for lists and explanations of available headers. The official home of the internet RFC documents is the IETF web site at http://www.ietf.org/home.html.
The following example sets the header for a POST request.