merge PR: dotnet#351

Author: AndrewKostousov

src/Docker.DotNet/Microsoft.Net.Http.Client/BufferedReadStream.cs

@@ -218,6 +218,9 @@ private async Task EnsureBufferedAsync(CancellationToken cancel)
 #else
                 _bufferCount = await _inner.ReadAsync(_buffer, _bufferOffset, _buffer.Length, cancel).ConfigureAwait(false);
 #endif
+
+                ThrowIfDisposed();
+
                 if (_bufferCount == 0)
                 {
                     throw new IOException("Unexpected end of stream");

test/Docker.DotNet.Tests/ISystemOperations.Tests.cs

@@ -90,7 +90,16 @@ public async Task MonitorEventsAsync_Succeeds()
             await _client.Images.DeleteImageAsync($"{repository}:{tag}", new ImageDeleteParameters());
         }
 
-        
+        [Fact]
+        public async Task MonitorEventsAsync_EmptyContainersList_CanBeCancelled()
+        {
+            var cts = new CancellationTokenSource();
+            cts.CancelAfter(1000);
+
+            var task = _client.System.MonitorEventsAsync(new ContainerEventsParameters(), new Progress(), cts.Token);
+
+            await task;
+        }
 
         class Progress : IProgress<Message>
         {