Yan Chen vagra

## routines.go
package main

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

func worker(wg *sync.WaitGroup, ctx context.Context, i int, ci <-chan int, co chan<- string) {
	package main

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

	func worker(wg *sync.WaitGroup, ctx context.Context, i int, ci <-chan int, co chan<- string) {