remove DocumentBuffer class

sdk/monitor/Azure.Monitor.OpenTelemetry.AspNetCore/src/LiveMetrics/DataCollection/DoubleBuffer.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
+using System.Collections.Concurrent;
 using Azure.Monitor.OpenTelemetry.AspNetCore.Models;
 
 namespace Azure.Monitor.OpenTelemetry.AspNetCore.LiveMetrics.DataCollection
@@ -14,17 +15,17 @@ namespace Azure.Monitor.OpenTelemetry.AspNetCore.LiveMetrics.DataCollection
     /// </summary>
     internal class DoubleBuffer
     {
-        private DocumentBuffer _currentBuffer = new();
+        private ConcurrentQueue<DocumentIngress> _currentBuffer = new();
 
         public void WriteDocument(DocumentIngress document)
         {
-            _currentBuffer.Add(document);
+            _currentBuffer.Enqueue(document);
         }
 
-        public DocumentBuffer FlipDocumentBuffers()
+        public ConcurrentQueue<DocumentIngress> FlipDocumentBuffers()
         {
             // Atomically exchange the current buffer with a new empty buffer and return the old buffer
-            return Interlocked.Exchange(ref _currentBuffer, new DocumentBuffer());
+            return Interlocked.Exchange(ref _currentBuffer, new ConcurrentQueue<DocumentIngress>());
         }
     }
 }

sdk/monitor/Azure.Monitor.OpenTelemetry.AspNetCore/src/LiveMetrics/Manager.Metrics.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License.
 
+using System.Collections.Concurrent;
 using Azure.Monitor.OpenTelemetry.AspNetCore.LiveMetrics;
 using Azure.Monitor.OpenTelemetry.AspNetCore.LiveMetrics.DataCollection;
 using Azure.Monitor.OpenTelemetry.AspNetCore.LiveMetrics.Filtering;
@@ -45,9 +46,10 @@ public MonitoringDataPoint GetDataPoint()
             string projectionError = string.Empty;
             Dictionary<string, AccumulatedValues> metricAccumulators = CreateMetricAccumulators(_collectionConfiguration);
             LiveMetricsBuffer liveMetricsBuffer = new();
-            DocumentBuffer filledBuffer = _documentBuffer.FlipDocumentBuffers();
             IEnumerable<DocumentStream> documentStreams = _collectionConfiguration.DocumentStreams;
-            foreach (var item in filledBuffer.ReadAllAndClear())
+
+            ConcurrentQueue<DocumentIngress> filledBuffer = _documentBuffer.FlipDocumentBuffers();
+            while (filledBuffer.TryDequeue(out DocumentIngress? item))
             {
                 bool matchesDocumentStreamFilter = false;