default port if other than 80 nor specified in URL
object Id of client to be notified when request complete
When the result of the request is available, the client is sent a
dataRead message and passed the parsed result of the response.
If unsuccessful, this will be nil; otherwise it is a three-element array.
Subscript 0 will be the MIME header; subscript 1 will contain the entity body;
subscript 2 will be the initial HTTP response status header.