Add histogram (#27544)

* add histogram

* add comment on count

* Typecast by shift.

* revert

* add histogram to supported

Co-authored-by: Rajkumar Rangaraj <[email protected]>

Author: vishweshbankwar

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/src/Customizations/Models/MetricData.cs

@@ -54,6 +54,14 @@ public MetricsData(int version, Metric metric, MetricPoint metricPoint) : base(v
                         DataPointType = DataPointType.Measurement
                     };
                     break;
+                case MetricType.Histogram:
+                    metricDataPoint = new MetricDataPoint(metric.Name, metricPoint.GetHistogramSum());
+                    metricDataPoint.DataPointType = DataPointType.Aggregation;
+                    long histogramCount = metricPoint.GetHistogramCount();
+                    // Current schema only supports int values for count
+                    // if the value is within integer range we will use it otherwise ignore it.
+                    metricDataPoint.Count = (histogramCount <= int.MaxValue && histogramCount >= int.MinValue) ? (int?)histogramCount : null;
+                    break;
             }
 
             metricDataPoints.Add(metricDataPoint);
@@ -73,6 +81,7 @@ internal static bool IsSupportedType(MetricType metricType) =>
                 MetricType.DoubleSum => true,
                 MetricType.LongGauge => true,
                 MetricType.LongSum => true,
+                MetricType.Histogram => true,
                 _ => false
             };
     }