常见Reader,Writer,buffer

Reader创建

r1 :=strings.NewReader("this is a Reader")

r2 :=bufio.NewReader(os.Stdin)
r2.ReadString('\n')

//os 的Open Create 返回的都是*File, 而File实现了io.Reader io.Writer
os.Open("a.png")
os.Create("b.jpg")

Writer创建

os.Stdout
http.ResponseWriter

buffer

b :=make([]byte,1024)

error创建

err := error.New("this is a error tip")