start method
Start the executor.
Implementation
@override
@nonVirtual
void start() {
  _isStarting = true;
  info('Starting $this - $configuration');
  _stateMachine.start();
}Start the executor.
@override
@nonVirtual
void start() {
  _isStarting = true;
  info('Starting $this - $configuration');
  _stateMachine.start();
}