I notice the Mailbox type is encapsulated and can only be used through the use of the MailboxProcessor.
It implies that to have an agent to which I can post messages, I'm forced to have a single Mailbox of a single type (or use the existing MailboxProcessor in an exotic way).
Should I understand that having multiple Mailbox for a single workflow would inherently result in a bad design? The Ccr clearly gives you that level of freedom.
Edit: As Daniel pointed out, if one wants to send multiple message types, DUs elegantly solves the problem - and it's not like I haven't done that in the past.
But the question is, isn't doing that a code smell? Wouldn't adding more types of messages sent to an agent over time lead you into have too many responsibilities? I sometimes think it would be important to always encapsulate the message types the agent consumes behind an interface such that this information is never exposed.
I think I may have found what I was looking for. I have listened to Rich Hickey's talk (Are we there yet) at least 5 times and I believe his approach solves many of the design concerns I had. Obviously this can be implemented with either F# Mailboxes or CAS references.
I really recommend it and would be happy to hear some feedback.