Helper function used in service implementations to finish handling invocations of the <link linkend="gdbus-method-org-freedesktop-cbd.
OpenMessages">OpenMessages</link> D-Bus method. If you instead want to finish handling an invocation by returning
an error, use return_error or similar.
This method will free invocation, you cannot use it afterwards.
| this |
A DBusCbd. |
| invocation | |
| result |
Parameter to return. |