This is the analogy I used to remember this rule:
1) go out of your house (outgoing message), wear socks (logical handler ) and then wear shoes (message handler)
2) get inside your house (incoming message) , take off your shoes (message handler) and then take off your socks (logical handler).
Proudly marching to the beat of a different kettle of fish... while reading this tiny ad
Devious Experiments for a Truly Passive Greenhouse!