A Live Activity for the active walk

ActivityKit's two-part shape: static vs. dynamic

A Live Activity is described by one type you define, conforming to ActivityAttributes. It splits into two kinds of data:

• Static attributes — set once, when the activity starts, and never change for its whole lifetime: the booking id, the walker's name. These are plain properties on the ActivityAttributes-conforming struct.

• Dynamic content state — the part that updates live while the walk is happening: elapsed seconds, distance walked so far. This lives in a nested type named ContentState, conforming to Codable and Hashable (so the system can serialize and compare it, including over a push notification).

The Lock Screen banner and the Dynamic Island both render from the current ContentState — same data, different presentation depending on where iOS shows it.