goroutine或多线程在golang中不起作用

I was trying to implement multithreading in golang. I am able to implement go routines but it is not working as expected. below is the sample program which i have prepared,

func test(s string, fo *os.File) {
    var s1 [105]int
    count :=0
    for x :=1000; x<1101;x++ {
    s1[count] = x;
        count++
    }

    //fmt.Println(s1[0])
    for i := range s1 {
        runtime.Gosched() 
        sd := s + strconv.Itoa(i)
        var fileMutex sync.Mutex
        fileMutex.Lock()
        fmt.Fprintf(fo,sd)
        defer fileMutex.Unlock()
    }
}

func main() {
    fo,err :=os.Create("D:/Output.txt")
    if err != nil {
        panic(err)
    }
    for i := 0; i < 4; i++ {
        go test("bye",fo) 

    }



}

OUTPUT - good0bye0bye0bye0bye0good1bye1bye1bye1bye1good2bye2bye2bye2bye2.... etc. the above program will create a file and write "Hello" and "bye" in the file.

My problem is i am trying to create 5 thread and wanted to process different values values with different thread. if you will see the above example it is printing "bye" 4 times.

i wanted output like below using 5 thread,

good0bye0good1bye1good2bye2....etc....

any idea how can i achieve this?