swiftmailer:
    default_mailer: secondary_mailer
    mailers:
        first_mailer:
            transport:  smtp
            username:   user_first
            password:   pass_first
            host:       example.org
            port:       12345
            encryption: tls
            auth-mode:  login
            timeout:    1000
            source_ip:  127.0.0.1
            logging:    true
            sender_address: first-sender@example.org
            delivery_address: first@example.org
            delivery_whitelist:
                - /firstfoo@.*/
                - /.*@firstbar.com$/
        secondary_mailer:
            transport:  smtp
            username:   user_secondary
            password:   pass_secondary
            host:       example.org
            port:       54321
            encryption: tls
            auth-mode:  login
            timeout:    1000
            source_ip:  127.0.0.1
            logging:    true
            spool:
                type: memory
            delivery_address: secondary@example.org
            delivery_whitelist:
                - /secondaryfoo@.*/
                - /.*@secondarybar.com$/
        third_mailer:
            transport:  smtp
            username:   user_third
            password:   pass_third
            host:       example.org
            port:       12345
            encryption: tls
            auth-mode:  login
            timeout:    1000
            source_ip:  127.0.0.1
            logging:    true
            spool:
                type: file
            sender_address: third-sender@example.org
            delivery_address: third@example.org
            delivery_whitelist:
                - /thirdfoo@.*/
                - /.*@thirdbar.com$/