When the implementation invokes the asynchronous teardown function, it always uses an invokable completion handler. It is not necessary to specify the return type customization when creating user-defined overloads of `async_teardown`.
When the implementation invokes the asynchronous teardown function, it always uses an invokable completion handler. It is not necessary to specify the return type customization when creating user-defined overloads of `async_teardown`.