class ActionMailer::LogSubscriber

def deliver(event)
  info do
    if exception = event.payload[:exception_object]
      "Failed delivery of mail #{event.payload[:message_id]} error_class=#{exception.class} error_message=#{exception.message.inspect}"
    elsif event.payload[:perform_deliveries]
      "Delivered mail #{event.payload[:message_id]} (#{event.duration.round(1)}ms)"
    else
      "Skipped delivery of mail #{event.payload[:message_id]} as `perform_deliveries` is false"
    end
  end
  debug { event.payload[:mail] }
end