Horusiath

// Delivery mechanism looks like this - if sender wants to reliably deliver payload to recipient 
// using at-least-once delivery semantics, it sends that payload wrapped to Messenger actor, which 
// is responsible for the persistence and redelivery:
//
//  +--------+                      +-----------+                    +-----------+
//  |        |--(DeliverOrder<T>)-->|           |--(Delivery<T>:1)-->|           |
//  |        |                      |           |  /* 2nd attempt */ |           |
//  | Sender |                      | Messenger |--(Delivery<T>:2)-->| Recipient |
//  |        |                      |           |                    |           |
//  |        |                      |           |<----(Confirm:2)----|           |