package main

import (
  "fmt"
  "sync"
  "time"
)

type someDataStruct struct {
  Val int
}

var wg sync.WaitGroup

func main() {

  t1 := time.Now()

  tasks := make(chan someDataStruct, 40)

  for i := 0; i < 40; i++ {
    wg.Add(1)

    go func() {
      for data := range tasks {
        // do some work on data
        fmt.Println(data.Val + 1)
      }
      wg.Done()
    }()

    someData := someDataStruct{i}
    // Push to it like this:
    tasks <- someData
  }

  // Finish like this
  close(tasks)
  wg.Wait()

  t2 := time.Now()
  fmt.Println("消耗时间：", t2.Sub(t1), "秒")
}