If mpv writes this struct (e.g. via mpv_get_property()), you must not change
the data. In some cases (mpv_get_property()), you have to free it with
mpv_free_node_contents(). If you fill this struct yourself, you're also
responsible for freeing it, and you must not call mpv_free_node_contents().
Type of the data stored in this struct. This value rules what members in
the given union can be accessed. The following formats are currently
defined to be allowed in mpv_node:
Generic data storage.
If mpv writes this struct (e.g. via mpv_get_property()), you must not change the data. In some cases (mpv_get_property()), you have to free it with mpv_free_node_contents(). If you fill this struct yourself, you're also responsible for freeing it, and you must not call mpv_free_node_contents().