all goroutines are asleep - deadlock

[qiangmzsx]

func PromisePipelining1()  {
    task1 := func() (r interface{}, err error) {
        return 10, errors.New("error")
    }
    task2 := func(v interface{}) (r interface{}, err error) {
        return v.(int) * 2, nil
    }

    f,ok := promise.Start(task1).Pipe(task2)
    if ok {
        r, err := f.Get()   //return 20
        fmt.Println(r,err)
    }

}

fatal error: all goroutines are asleep - deadlock!

goroutine 1 [chan receive]:
github.com/fanliao/go-promise.(*Future).Get(0xc0420b8980, 0xc042083f38, 0x1, 0x1, 0xc0420b8980)
	D:/Code/golang/src/github.com/fanliao/go-promise/future.go:138 +0x4f
main.PromisePipelining1()
	D:/Code/golang/src/studygo/futrue/future.go:148 +0xd4
main.main()
	D:/Code/golang/src/studygo/futrue/future.go:16 +0x27
exit status 2