l := NewReaderSize(buf, minReadBufferSize)
	line, isPrefix, err := l.ReadLine()
	if !isPrefix || !bytes.Equal(line, data[:minReadBufferSize]) || err != nil {
		t.Errorf("bad result for first line: got %q want %q %v", line, data[:minReadBufferSize], err)
	}
	data = data[len(line):]
	line, isPrefix, err = l.ReadLine()
	if !isPrefix || !bytes.Equal(line, data[:minReadBufferSize]) || err != nil {