我们可以使用"承诺"像这样的东西:
const pm = new Promise((resolved,rejected)=>.....);
const result = yield pm;
我们无法获取待处理状态,如何处理?我需要这样的东西:
const pm = new Promise((***pending***,resolved,rejected)=>....);
const result = yield pm; //the result from pending state,resolved and rejected