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