const wantString = testPayload + testPayload
		if resp.OrgString != testPayload+testPayload {
			t.Errorf("want %q, got %q", wantString, resp.OrgString)
		}
		if resp.OrgNum != n+1 {
			t.Errorf("want %d, got %d", n+1, resp.OrgNum)
		}
		handler.PutResponse(resp)
		n++
		return nil
	})
	errFatal(err)
	t.Log("EOF.", payloads, " Roundtrips:", time.Since(start))
}