I think it's on you - as the receiver of a message - to appropriately deal with your messaging app of choice such that it doesn't interupt your flow. Otherwise, you are placing an impossible burden on the sender of the message to some how telepathically know if it's a good time. IMHO, your preferred workflow makes it seem that your time is more valuable than the other person's as you're now asking them to hang around waiting until they can actually ask their question.
The asynchronous nature of messaging is important to preserve.
The asynchronous nature of messaging is important to preserve.