This struct defines a single action. It is for use with Action.mapAddActionEntries.
The order of the items in the structure are intended to reflect frequency of use. It is permissible to use an incomplete initialiser in order to leave some of the later values as NULL. All values after name are optional. Additional optional fields may be added in the future.
See Action.mapAddActionEntries for an example.
the name of the action
the type of the parameter that must be passed to the activate function for this action, given as a single GVariant type string (or NULL for no parameter)
the initial state for this action, given in [GVariant text format][gvariant-text]. The state is parsed with no extra type information, so type tags must be added to the string if they are necessary. Stateless actions should give NULL here.