[Swan-dev] enum message_role

[D. Hugh Redelmeier]

Why do the "real" values start at 3?

In general, I prefer to let the compiler pick values of enums.  (Of course 
that makes no sense if the values are specified by the IETF.)

- the compiler makes fewer mistakes
   (I think that we have had bugs where the same value was asssigned 
   twice.)

- it removes a burden from the programmer

- it leaves unimportant details out of the code

- it indicates that the values are unimportant