CSHARP-6029: Make ICoreServerSessionPool disposable and send endSessions on dispose - fix failing tests

Author: sanych-sun

src/MongoDB.Driver/Core/Bindings/CoreServerSessionPool.cs

@@ -114,6 +114,11 @@ public void CloseAndDispose(IServer server)
                 while (true)
                 {
                     var batchSize = Math.Min(10000, _pool.Count);
+                    if (batchSize == 0)
+                    {
+                        return;
+                    }
+
                     var batch = new ICoreServerSession[batchSize];
 
                     batchSize = _pool.TryPopRange(batch);

tests/SmokeTests/MongoDB.Driver.SmokeTests.Sdk/OpenTelemetryTests.cs

@@ -48,13 +48,13 @@ public void MongoClient_should_create_activities_when_tracing_enabled()
                 ClusterRegistry.Instance.UnregisterAndDisposeCluster(mongoClient.Cluster);
             }
 
-            capturedActivities.Should().HaveCount(6);
+            capturedActivities.Should().HaveCount(7);
 
             var operationActivities = capturedActivities.Where(a => a.GetTagItem("db.operation.name") != null).ToList();
             var commandActivities = capturedActivities.Where(a => a.GetTagItem("db.command.name") != null).ToList();
 
             operationActivities.Should().HaveCount(3);
-            commandActivities.Should().HaveCount(3);
+            commandActivities.Should().HaveCount(4);
         }
 
         [Fact]