update cron example

_examples/cron/Makefile

@@ -1,6 +1,6 @@
 .PHONY: dev
 dev:
-	wrangler dev
+	wrangler dev --test-scheduled
 
 .PHONY: build
 build:

_examples/cron/README.md

@@ -18,3 +18,12 @@ make dev     # run dev server
 make build   # build Go Wasm binary
 make deploy # deploy worker
 ```
+
+#### Testing cron schedule
+
+* With curl command below, you can test the cron schedule.
+  - see: https://developers.cloudflare.com/workers/runtime-apis/handlers/scheduled/#background
+
+```
+curl "http://localhost:8787/__scheduled?cron=*+*+*+*+*"
+```

_examples/cron/main.go

@@ -3,7 +3,9 @@ package main
 import (
 	"context"
 	"fmt"
+	"time"
 
+	"github.com/syumai/workers/cloudflare"
 	"github.com/syumai/workers/cloudflare/cron"
 )
 
@@ -15,6 +17,11 @@ func task(ctx context.Context) error {
 
 	fmt.Println(e.ScheduledTime.Unix())
 
+	cloudflare.WaitUntil(func() {
+		time.Sleep(1 * time.Second)
+		fmt.Println("Run sub task after returning from main task")
+	})
+
 	return nil
 }