How to get content from a url in Go

package main

import (
  "io/ioutil"
  "net/http"
)

func main() {

  url := "https://go.dev/"

  resp, err := http.Get(url)
  if err != nil {
    // panic
  }
  defer resp.Body.Close()
  b, err := ioutil.ReadAll(resp.Body)

  // upload image
  resp, err := http.Post("http://example.com/upload", "image/jpeg", &buf)

  // post form
  resp, err := http.PostForm("http://example.com/form", url.Values{"key": {"Value"}, "id": {"123"}})

}

client := &http.Client{
  CheckRedirect: redirectPolicyFunc,
}

resp, err := client.Get("http://example.com")
// ...

req, err := http.NewRequest("GET", "http://example.com", nil)
// ...
req.Header.Add("If-None-Match", `W/"wyzzy"`)
resp, err := client.Do(req)
// ...

// For control over proxies ...
tr := &http.Transport{
  MaxIdleConns:       10,
  IdleConnTimeout:    30 * time.Second,
  DisableCompression: true,
}
client := &http.Client{Transport: tr}
resp, err := client.Get("https://example.com")

package main

import (
  "fmt"
  "io"
  "io/ioutil"
  "net/http"
  "time"
)

func fetch(url string, ch chan<- string) {
  start := time.Now()
  resp, err := http.Get(url)
  if err != nil {
    ch <- fmt.Sprint(err) // send to channel ch
    return
  }
  defer resp.Body.Close()

  nbytes, err := io.Copy(ioutil.Discard, resp.Body)
  if err != nil {
    ch <- fmt.Sprintf("while reading %s: %v", url, err)
    return
  }
  secs := time.Since(start).Seconds()
  ch <- fmt.Sprintf("%.2fs  %7d  %s", secs, nbytes, url)
}

func main() {

  urls := []string{"https://go.dev/", "https://www.google.com/"}

  ch := make(chan string)
  for _, url := range urls {
    go fetch(url, ch)
  }

  for range urls {
    fmt.Println(<-ch) // receive from channel ch
  }

}

0.95s    15227  https://www.google.com/
1.13s    58557  https://go.dev/