有懂 golang 的吗，可以解释下这段代码吗？

package main

import (
	"fmt"
	"sync"
)

type Job interface {
	Do()
}
type Worker struct {
	id         int
	jobChannel chan Job
	done       chan bool
}
type Pool struct {
	workers  []*Worker
	jobQueue chan Job
	wg       sync.WaitGroup
}

func NewWorker(id int, wg *sync.WaitGroup) *Worker {
	worker := Worker{
		id:         id,
		jobChannel: make(chan Job),
		done:       make(chan bool),
	}
	go func() {
		for job := range worker.jobChannel {
			job.Do()
		}
		wg.Done()
	}()
	return &worker
}
func NewPool(numWorkers int) *Pool {
	pool := Pool{
		workers:  make([]*Worker, numWorkers),
		jobQueue: make(chan Job),
	}
	for i := 0; i < numWorkers; i++ {
		pool.workers[i] = NewWorker(i, &pool.wg)
	}
	go pool.run()
	return &pool
}
func (w *Worker) Start(job Job) {
	w.jobChannel <- job
}
func (w *Worker) Stop() {
	close(w.jobChannel)
	<-w.done
}
func (p *Pool) run() {
	for job := range p.jobQueue {
		worker := p.getAvailableWorker()
		worker.Start(job)
	}
	for _, worker := range p.workers {
		worker.Stop()
	}
	p.wg.Done()
}
func (p *Pool) getAvailableWorker() *Worker {
	for {
		for _, worker := range p.workers {
			select {
			case <-worker.done:
			default:
				return worker
			}
		}
	}
}
func (p *Pool) Submit(job Job) {
	p.wg.Add(1)
	p.jobQueue <- job
}
func (p *Pool) Shutdown() {
	close(p.jobQueue)
	p.wg.Wait()
}

type PrintJob struct {
	id int
}

func (pj PrintJob) Do() {
	fmt.Printf("Printing job %d\n", pj.id)
}
func main() {
	pool := NewPool(5)
	for i := 0; i < 10; i++ {
		pool.Submit(PrintJob{id: i})
	}
	pool.Shutdown()
}