Can the on_cmd method of the extension have a return value

[halajohn]

If we want to inherit the extension, can the on_cmd method of the extension have a return value? Otherwise, it will be difficult to handle in the parent class. The subclass can't determine whether the parent class has already processed the command, and if it hasn't, based on the current logic, there must be a return result as a fallback. Otherwise, the thread will get stuck.

We need to consider the meaning of the return value in the current situation where it's not in the base class/child class.