code: function extractSrt (buffer) {
    const zip = new AdmZip(buffer)
    const srtZipEntry = zip
      .getEntries()
      .find(zipEntry =>
        zipEntry.entryName.endsWith('.srt')
      )
    return zip.readAsText(srtZipEntry)
  }
docs: Extract the first .srt file found in the given ZIP buffer.
  
  @param {Buffer} buffer
  @returns {string} the content of the first .srt file found in the given ZIP