diff --git a/PolyShim.Tests/NetCore30/StreamTests.cs b/PolyShim.Tests/NetCore30/StreamTests.cs
new file mode 100644
index 0000000..380bdec
--- /dev/null
+++ b/PolyShim.Tests/NetCore30/StreamTests.cs
@@ -0,0 +1,26 @@
+using System.IO;
+using System.Threading.Tasks;
+using FluentAssertions;
+using Xunit;
+
+namespace PolyShim.Tests.NetCore30;
+
+public class StreamTests
+{
+    [Fact]
+    public async Task DisposeAsync_Test()
+    {
+        // Arrange
+        var innerStream = new MemoryStream();
+
+        // Use a buffered stream to ensure DisposeAsync flushes data
+        var stream = new BufferedStream(innerStream, bufferSize: 4096);
+        await stream.WriteAsync(new byte[] { 1, 2, 3, 4, 5 });
+
+        // Act
+        await stream.DisposeAsync();
+
+        // Assert
+        innerStream.ToArray().Should().Equal(1, 2, 3, 4, 5);
+    }
+}
diff --git a/PolyShim/NetCore30/Stream.cs b/PolyShim/NetCore30/Stream.cs
index 81b1d93..adb68ee 100644
--- a/PolyShim/NetCore30/Stream.cs
+++ b/PolyShim/NetCore30/Stream.cs
@@ -27,7 +27,14 @@ public async Task DisposeAsync()
             }
 #endif
 
-            await Task.Run(stream.Dispose);
+            try
+            {
+                await stream.FlushAsync();
+            }
+            finally
+            {
+                stream.Dispose();
+            }
         }
 #endif
     }
diff --git a/PolyShim/NetCore30/TextWriter.cs b/PolyShim/NetCore30/TextWriter.cs
index 216aca5..4c91552 100644
--- a/PolyShim/NetCore30/TextWriter.cs
+++ b/PolyShim/NetCore30/TextWriter.cs
@@ -27,7 +27,14 @@ public async Task DisposeAsync()
             }
 #endif
 
-            await Task.Run(writer.Dispose);
+            try
+            {
+                await writer.FlushAsync();
+            }
+            finally
+            {
+                writer.Dispose();
+            }
         }
 #endif
     }