AddMenuItem adds a menu item with the designated title and tooltip.

AddMenuItemCheckbox adds a menu item with the designated title and tooltip and a checkbox for Linux.

AddSeparator adds a separator bar to the menu.

Quit the systray.

Register initializes GUI and registers the callbacks but relies on the caller to run the event loop somewhere else.

Run initializes GUI and starts the event loop, then invokes the onReady callback.

MenuItem is used to keep track each menu item of systray.