promiseRace

输入的 stream 或者 subjection 进行竞争，返回一个新的流，fork最先推送数据的那个流

• 类型

  type promiseRace: (...args: (Stream | Subjection)[]) => Stream;

• 详情

  • 输入的流取消订阅或者结束后，新的流也会取消订阅或者结束

• 示例

  import { $, promiseRace } from "fluth";
  
  const stream1$ = $(1);
  const stream2$ = $("hello");
  const stream3$ = $(false);
  
  const promiseRace$ = promiseRace(stream1$, stream2$, stream3$);
  promiseRace$.then((value) => console.log(value));
  
  stream2$.next("world");
  // 打印："hello"
  stream3$.next(true);
  stream1$.next(3);
  stream2$.next("code");
  // 打印："code"