act property

A MessageActionBuilder that can be used to specify actions that should take place when handling messages.

class MyMessage {}
var state1 = StateKey('s1');
var state2 = StateKey('s2');
var builder = StateTreeBuilder(initialState: state1);
builder.state(state1, (b) {
  b.onMessage<MyMessage>((b) => b.goTo(
    state2,
    // Perform an action before state transition occurs.
    action: b.act.run((msgCtx, msg) =>
      print('Going to $state2 in response to message $msg')));
});