data property
Received property value. Depends on the format. This is like the pointer argument passed to mpv_get_property().
For example, for MPV_FORMAT_STRING you get the string with:
char *value = *(char **)(event_property->data);
Note that this is set to NULL if retrieving the property failed (the format will be MPV_FORMAT_NONE).
Implementation
external ffi.Pointer<ffi.Void> data;