【Go】NewRequestWithContextを試す

package main

import (
    "context"
    "net/http"
    "time"
)

func main() {
    ctx := context.Background()
    ctx, cancel := context.WithCancel(ctx)

    req, _ := http.NewRequestWithContext(ctx, "GET", "http://httpbin.org/delay/3", nil) // it will return later 3 sec

    client := &http.Client{}

    go func() {
        time.Sleep(time.Second * 2)
        println("Cancel")
        cancel()
    }()

    println("Do")
    resp, err := client.Do(req)
    println("Do finished")

    if err != nil {
        panic(err) // cancel caught
    }

    println(resp.StatusCode)
}