Thanks. My personal use case is a client with business logic written in Go with intermittent connectivity, some data is private to the device, some private to the server, and with some data synced from server to clients. Many events are time critical and need instant updates.

To me it’s more general than that though. The expectation of having reactive behavior comes up everywhere from chat apps to collaborative to even games. Polling and refreshing feels very 90s and ”web page centric” but of course in some cases (say long form blogging or similar) it’s not a concern.