public Task <TResponse> StartTrialAsync <TResponse>(StartTrialLicenseRequestParameters requestParameters = null, CancellationToken ctx = default)
     where TResponse : class, ITransportResponse, new() => DoRequestAsync <TResponse>(POST, "_license/start_trial", ctx, null, RequestParams(requestParameters));
 ///<summary>POST on /_license/start_trial <para>https://www.elastic.co/guide/en/elasticsearch/reference/master/start-trial.html</para></summary>
 ///<param name = "requestParameters">Request specific configuration such as querystring parameters &amp; request specific connection settings.</param>
 public TResponse StartTrial <TResponse>(StartTrialLicenseRequestParameters requestParameters = null)
     where TResponse : class, ITransportResponse, new() => DoRequest <TResponse>(POST, "_license/start_trial", null, RequestParams(requestParameters));