Logging of custom mail headers

Hi,

I need to configure Dovecot to log some custom mail headers.

I red the documentation of the mail_log plugin but I didn't found which field I've to use as value for mail_log_fields parameter.

So, I red the plugin code but in mail-log-plugin.c there're defined only "from" and "subject" fields that match some email header.

I found three alternatives:

1. use the mail_filter plugin (spawning a new process, ecc.)

2. coding a new plugin using the notify plugin

3. propose a patch to the mail_log plugin that use a new configuration parameter (es. mail_log_headers) and log the specified mail headers

Which is the better solution for you?

Thanks in advance

Francesco