name of zeitgeist_event_set_payload does not indicate ownership transfer

[Simon McVittie]

Functions that take ownership of a "full" (not floating) reference, i.e. (transfer full) in GObject-Introspection notation, are generally called foo_take_bar(). A function called foo_set_bar() is usually (transfer none).

If you wanted to make this clearer without breaking API, it would be possible to add a zeitgeist_event_take_payload() (with the same semantics) and deprecate zeitgeist_event_set_payload(), for instance.