Register an alert channel. Throws if definition.name is already taken —
a name collision between two plugins (or a plugin and a built-in) is a
configuration error that should fail loudly at startup, not silently
shadow one implementation with another.
Register an alert channel. Throws if
definition.nameis already taken — a name collision between two plugins (or a plugin and a built-in) is a configuration error that should fail loudly at startup, not silently shadow one implementation with another.