interface CustomFulfillmentProcess<State extends keyof CustomFulfillmentStates | string> extends InjectableStrategy {
  transitions?: Transitions<State, State | FulfillmentState> &
        Partial<Transitions<FulfillmentState | State>>;
  onTransitionStart?: OnTransitionStartFn<State | FulfillmentState, FulfillmentTransitionData>;
  onTransitionEnd?: OnTransitionEndFn<State | FulfillmentState, FulfillmentTransitionData>;
  onTransitionError?: OnTransitionErrorFn<State | FulfillmentState>;
}