功能：一个轻量的goroutine pool实现，它由Job、dispatcher、work、pool组成。通过pool.put投放job到pool中，dispatcher负责分发job到可用的worker中，然后worker执行job，自定义job实现Job的Exec方法即可。执行完job后返回pool。
//工作池，将Job投放到JobQueue中
type Pool struct {
//投放job的chan
JobQueue chan Job
//调度中心分派器
dispatcher *Dispatcher
//waitgroup
wg sync.WaitGroup
}
//调度中心分派器，从jobQueue中获取Job，从workerPool中获取一个可用worker，然后将Job投放到worker的jobChannel中
type Dispatcher struct {
workerPool chan *Worker
jobQueue chan Job
stop chan struct{}
}
//Worker 工作者单元, 用于执行Job的单元, 从jobChannel中获取Job
type Worker struct {
workerPool chan *Worker
jobChannel chan Job
stop chan struct{}
}
type MyJob struct {
Num uint64
Pool *Pool
}
func (m *MyJob) Exec() error {
defer t.Pool.JobDone()
log.Printf("I am worker! Number %d\n", m.Num)
return nil
}
pool := NewPool(1000, 10000)
defer pool.Release()
iterations := 100
pool.WaitCount(iterations)
arg := uint64(1)
for i := 0; i < iterations; i++ {
job := &MyJob{
Num: arg,
Pool: pool,
}
atomic.AddUint64(&arg, 1)
pool.JobQueue <- job
}
pool.WaitAll()
log.Println("work run over")