run method

Runs handler when the transition occurs.

void handleEnter(TransactionContext ctx) => print('State entered');
void handleExit(TransactionContext ctx) => print('State exited');

var state1 = StateKey('s1');
var builder = StateTreeBuilder(initialState: state1);

builder.state(state1, (b) {
  // Run a function when the state is entered
  b.onEnter((b) => b.run(handleEnter));

  // Run a function when the state is exited
  b.onExit((b) => b.run(handleExit));
});

The handler can be labeled when formatting a state tree by providing a label.