Timber parses the Heroku log format which is outlined as following the Syslog 5424 specification. In practice these messages look like:
83 <40>1 2012-11-30T06:45:29+00:00 host app web.3 - State changed from starting to up
119 <40>1 2012-11-30T06:45:26+00:00 host app web.3 - Starting process with command `bundle exec rackup config.ru -p 24405`
Timber will map these fields to their appropriate Timber log event JSON schema fields. Speficially, the
context.platform fields which have Heroku specific fields for the dyno type and ID.