constructor

const StateAnnotation = Annotation.Root({
  messages: Annotation<string[]>({ reducer: (a, b) => [...a, ...b] }),
});
const graph = new StateGraph(StateAnnotation);

const graph = new StateGraph(StateAnnotation, {
  input: InputSchema,
  output: OutputSchema,
});

const graph = new StateGraph({
  state: FullStateSchema,
  input: InputSchema,
  output: OutputSchema,
});

const graph = new StateGraph({
  input: InputAnnotation,
  output: OutputAnnotation,
});