This method is called for every line in the log file(s). If this line has already been handled by another agent, handled will be true. This is just informative, you can still do whatever you want with the line. If another agent already consumed this line, then this will never be called.

Returns one of {:unhandled, :handled, :consumed}

This method is called after all lines have been fed to handle().

Returns a string suitable for the body of an email (e.g. wrapped at 72 characters wherever possible, etc.)