The Authorization string to be sent to the server.
If the Authorization property contains a non-empty string, an Authorization HTTP request header is added to the request. This header conveys Authorization information to the server.
A common use for this property is to specify OAuth authorization string.
This property is provided so that the HTTP control can be extended with other security schemes in addition to the authorization schemes already implemented by the control.
The AuthScheme property defines the authentication scheme used. In the case of HTTP Basic Authentication (default), every time User and Password are set, they are Base64 encoded, and the result is put in the Authorization property in the form "Basic [encoded-user-password]".