Calling rows.Err() in a multiple result set query with rows.NextResultSet()

I'm building a query with multiple result sets, following the example given, here. Important bits copied below for convenience.

My question is, should rows.Err() be called after each for rows.Next() {...} loop, rather than once at the very end as shown in the example? Why / why not? My understanding is that rows.Err() will catch errors, "... encountered during iteration", whereas rows.NextResultSet() will catch, "... [errors] advancing to [the next result set]". Seems like I would want to catch errors during each iteration, no? Thanks!

rows, err := db.Query(q, age)
if err != nil {
	log.Fatal(err)
}
defer rows.Close()

for rows.Next() {
	var (
		id   int64
		name string
	)
	if err := rows.Scan(&id, &name); err != nil {
		log.Fatal(err)
	}
	fmt.Printf("id %d name is %s\n", id, name)
}
if !rows.NextResultSet() {
	log.Fatal("expected more result sets", rows.Err())
}
var roleMap = map[int64]string{
	1: "user",
	2: "admin",
	3: "gopher",
}
for rows.Next() {
	var (
		id   int64
		role int64
	)
	if err := rows.Scan(&id, &role); err != nil {
		log.Fatal(err)
	}
	fmt.Printf("id %d has role %s\n", id, roleMap[role])
}
if err := rows.Err(); err != nil {
	log.Fatal(err)
}

You can find from source code of Next or Err or NextResultSet function that there is lasterr member of Rows structure which can be set by several ways and Err always return it if it isn't EOF.

Those ways are:

1. Next gets some error, sets lasterr and always returns false (so for rows.Next() {... doesn't iterate more and it is enough to check rows.Err() only after the loop.
2. NextResultSet also sets lasterr whenever it gets error and also returns false.

So answer is yes, it should. Because if NextResultSet after Next returns false its error replaces error from Next.