Shared Request - Shares a single request across multiple go routines

wait.go

package main

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

type SharedRequest struct {
	data    string
	loading bool
	lock    sync.Mutex
	wg      sync.WaitGroup
}

func (r *SharedRequest) Exec() {
	r.lock.Lock()
	defer r.lock.Unlock()
	if !r.loading {
		r.loading = true
		r.wg.Add(1)
		go func() {
			time.Sleep(5 * time.Second)
			r.wg.Done()
		}()
	}
}

func (r *SharedRequest) Wait() {
	r.wg.Wait()
}

func main() {
	req := &SharedRequest{}

	req.Wait()
	fmt.Println("Done")

	start := time.Now()

	for i := 0; i < 4; i++ {
		req.Exec()
	}

	time.Sleep(2 * time.Second)

	for i := 0; i < 4; i++ {
		req.Exec()
	}

	req.Wait()
	duration := time.Since(start)
	fmt.Println("Done", duration)
}