code: function remakeBody (body, bodyType) {
    return blobUtil
      .base64StringToBlob(body)
      .then(function (blob) {
        switch (bodyType) {
          case BodyTypes.ARRAY_BUFFER:
            return blobUtil.blobToArrayBuffer(blob)
          case BodyTypes.BLOB:
            return blob
          case BodyTypes.FORM_DATA:
            throw new Error('Cannot make FormData from serialised Request')
          case BodyTypes.JSON:
            return blobToString(blob)
              .then(function (str) {
                return JSON.parse(str)
              })
          case BodyTypes.TEXT:
            return blobToString(blob)
          default:
            throw new Error('Unknown requested body type "' + bodyType + '"')
        }
      })
  }
docs: Deserialise the body of a Request.
  @param {String} body
  @param {String} bodyType
  @returns {Promise}