code: function SendMessage (auth, apiVersion) {
    if (!(this instanceof SendMessage)) return new SendMessage(auth, apiVersion)
    this._noopCallback = function () {}
    this._headers = {
      'Accept': 'application/json',
      'Authorization': 'Basic ' + auth.basicAuth
    }
    this.versionNumber = apiVersion || 'v3'
    this.lastQueryTime = 0
    this.setContextPath()
  }
docs: The main constructor used for sending messages
  @param {Auth} auth       The authentication details
  @param {String} apiVersion The API version to use for request (Versioned API)