Function item_menu 

pub fn item_menu(placed: Vec<MenuPart>, offered: Vec<MenuPart>) -> Vec<MenuPart>

The menu of an item: the view’s own content first, as it placed it; then, after a separator, each command the item offers (offered, its allowed actions) that the view did not place, so every action stays reachable from the menu. A command is placed when the view has one that runs the same action on the same resource.