No way to escape markup

[The-Compiler]

When the markup capability is advertised, applications escape <, > and & in the data they send - see the notification spec and Ubuntu guidelines for details.

However, with linux_notification_center (the 1.7.2 release binary with default config), doing:

notify-send foo '<&lt foo > >'

leads to that text being displayed literally, while:

notify-send foo '<< foo >>'

doesn't display the body at all.