/// <summary>
 /// Begins reporting of a performance of a given type.
 /// </summary>
 /// <param name="performanceType">Performance type.</param>
 public void BeginPerformanceCategory(ReportableCategory performanceType)
 {
     EnsureNotFinalised();
     performanceType.RequireDefinedValue(nameof(performanceType));
     currentPerformanceType = performanceType;
 }