function makeManifest(lines) {
      const template = [
        '<MPD type="dynamic"',
        '     availabilityStartTime="1970-01-01T00:00:00Z"',
        '     timeShiftBufferDepth="PT60S"',
        '     maxSegmentDuration="PT5S"',
        '     suggestedPresentationDelay="PT0S">',
        '  %s',
        '  <Period>',
        '    <AdaptationSet mimeType="video/mp4">',
        '      <Representation bandwidth="500">',
        '        <BaseURL>http://example.com</BaseURL>',
        '        <SegmentList>',
        '          <SegmentURL media="s1.mp4" />',
        '          <SegmentTimeline>',
        '            <S d="5" t="0" />',
        '          </SegmentTimeline>',
        '        </SegmentList>',
        '      </Representation>',
        '    </AdaptationSet>',
        '  </Period>',
        '</MPD>',
      ].join('\n');
      return sprintf(template, lines.join('\n'));
    }
@param {!Array<string>} lines
@return {string}