time.sleep如何更改使用通道的程序的结果

Question

I am new in Go and doing some practices with the book "The little Go book" from chapter Concurrency. I can't figure out what happens by removing time.Sleep(time.Millisecond * 50)that changes the output to only printing results for "worker 4".

 package main

import (
    "fmt"
    "math/rand"
    "time"
)

func main() {
    c := make(chan int)
    for i := 0; i < 5; i++ {
        worker := &Worker{id: i}
        go worker.process(c)

    }
    for {
        c <- rand.Int()
        time.Sleep(time.Millisecond * 50) // ???
    }
}

type Worker struct {
    id int
}

func (w *Worker) process(c chan int) {
    for {
        data := <-c
        fmt.Printf("worker %d got %d
", w.id, data)
    }
}