This method is used to attach a display handle created outside of
the class using the SocketTools API. Once the handle is attached to
the class, the other class member functions may be used with that
virtual display.
The virtual display for the current instance of the class will be
destroyed when the new handle is attached to the class object. If you
want to prevent the display handle from being released, you must call
the DetachHandle method. Failure to release the detached
handle may result in a resource leak in your application.
Note that the hDisplay parameter is presumed to be a valid
display handle and no checks are performed to ensure that the handle
is valid. Specifying an invalid handle will cause subsequent method
calls to fail.