Last minute question due to manual testing :-)
When sending private messages to other nodes via the GUI (or cli since it will go the same controller) it seems to me that:
1. The private message shows on the sending node's log due to line `/controller.go:150`
2. [Unexpected] The private msg does *not* show on the receiver gossiper's log, because we only look at Simple/Rumor messages at `controller.go:234`.
Maybe this is a remnant of when students had to implement more parts of the the GUI? May we add code to the controller for manual testing?