[Mailmunge] filter_recipient()

[postfix at ptld.com]

> sub sub_function
> {
>     my ($self, $ctx) = @_;
>     if (some_condition()) {
>         return Mailmunge::Response->REJECT(msg => 'Go away');
>     }
>     return Mailmunge::Response->CONTINUE();
> }


In your example using "msg=>" is that pseudo code or is "msg" valid? In 
the docs i only see "message".

Are response argument keys case-sensitive? Nothing on 
https://www.mailmunge.org/docs/Mailmunge__Response.php says one way or 
the other, however some argument keys are listed in all upper case while 
some are lower case implying there is a difference. In particular 
"dsn=>" is lower case.

However on https://www.mailmunge.org/docs/Mailmunge__Filter__Compat.php 
there is an example giving for usage where "DSN=>" is upper case. Which 
is correct or is it case-insensitive?