#[OnActivation]
Attribute on methods.
Runs the method when the plugin is activated or the site switches to the theme (or child theme).
A plugin runs it in the request that activates it (activate_{plugin});
network-wide activation runs it once per site. A theme runs it on the first
request after the switch (after_switch_theme), unless the previous theme
was this theme or its child theme. The method is public, returns void and
takes services only.