code: function canonicalMd5(md5) {
    if (md5) {
      if (Buffer.isBuffer(md5))
        md5 = md5.toString('base64')
      else if (md5 && md5.match(/^md5-/))
        md5 = md5.replace(/^md5-/, '')
  
      if (md5.length === 32)
        md5 = new Buffer(md5, 'hex').toString('base64')
    }
    return md5
  }
docs: File class Because of toString = this.name, it can be used interchangeably as a string key, and also as the object represented by that