abstract fun unregisterCommand(commandName: String): CommandRegistry
Like #unregisterCommand(String, Handler), without a completion handler.
abstract fun unregisterCommand(commandName: String, completionHandler: Handler<AsyncResult<Void>>): CommandRegistry
Unregister a command.
commandName - the command name
completionHandler - notified when the command is unregistered
Return
a reference to this, so the API can be used fluently