func ExampleSectionReader_Size() {
	r := strings.NewReader("some io.Reader stream to be read\n")
	s := io.NewSectionReader(r, 5, 17)

	fmt.Println(s.Size())

	// Output:
	// 17
}

func ExampleSeeker_Seek() {
	r := strings.NewReader("some io.Reader stream to be read\n")

	r.Seek(5, io.SeekStart) // move to the 5th char from the start
	if _, err := io.Copy(os.Stdout, r); err != nil {
		log.Fatal(err)
	}