[plt-scheme] Serializable SRFI 19 times

Hi all,

I'm updating snooze.plt to make Snooze datatypes compatible with  
scheme/serialize (for some experiments with Jay's web language). I  
notice that SRFI 19 time structures are not serializable. This leaves  
me with two options:

   1. contribute a patch to SRFI 19 to make times (and possibly dates)  
serializable;
   2. change the way Snooze works so that times are stored internally  
as some other serializable data type.

I'd prefer to go with option 1, but that makes me wonder... is there  
any downside to making structs serializable? If so, option 2 obviously  
becomes more attractive.

Cheers,

-- Dave