阻塞channel优先返回给主线程

package main

import (
    ."fmt"
)

func fbi(num int,ch chan int){
    if num<3 {
        ch<-num;
    }else{
        /*
        cl:=make(chan int);
        go fbi(num-2,cl);
        tmp:=<-cl;
        cr:=make(chan int);
        go fbi(num-1,cr);
        tmp+=<-cr;
        ch<-tmp;
        */
        go fbi(num-2,ch);
        r:=<-ch;
        Println("in go");
        go fbi(num-1,ch);
        l:=<-ch;
        ch<- (l+r);
    }
}

func main(){
    ch:=make(chan int);
    go fbi(10,ch);
    Println(<-ch);
    Println("in main go");
}