I wrote this up:

> Be aware that received_at is the time when your IMAP account records the 
> message having arrived and indexed_at is when the message was the message
> was processed and indexed by the Context.io sync process.

Based on this:

```
[83] pry(main)> Time.at(m.date)
=> 2013-07-27 22:05:41 -0500
[84] pry(main)> m.received_at
=> 2013-07-27 22:05:47 -0500
[85] pry(main)> m.indexed_at
=> 2013-07-27 22:13:00 -0500
```

I expected `m.date` to be identical to `m.received_at` but it is different. Where is m.date determined and how is it different from received_at?