diff --git a/src/Microsoft.AspNetCore.WebUtilities/HttpResponseStreamWriter.cs b/src/Microsoft.AspNetCore.WebUtilities/HttpResponseStreamWriter.cs
index f5568fb4a3..4356693d58 100644
--- a/src/Microsoft.AspNetCore.WebUtilities/HttpResponseStreamWriter.cs
+++ b/src/Microsoft.AspNetCore.WebUtilities/HttpResponseStreamWriter.cs
@@ -16,11 +16,7 @@ namespace Microsoft.AspNetCore.WebUtilities
     public class HttpResponseStreamWriter : TextWriter
     {
         private const int MinBufferSize = 128;
-
-        /// <summary>
-        /// Default buffer size.
-        /// </summary>
-        public const int DefaultBufferSize = 1024;
+        internal const int DefaultBufferSize = 16 * 1024;
 
         private Stream _stream;
         private readonly Encoder _encoder;
@@ -50,39 +46,19 @@ namespace Microsoft.AspNetCore.WebUtilities
             ArrayPool<byte> bytePool,
             ArrayPool<char> charPool)
         {
-            if (stream == null)
-            {
-                throw new ArgumentNullException(nameof(stream));
-            }
-
             if (!stream.CanWrite)
             {
                 throw new ArgumentException(Resources.HttpResponseStreamWriter_StreamNotWritable, nameof(stream));
             }
 
-            if (encoding == null)
-            {
-                throw new ArgumentNullException(nameof(encoding));
-            }
+            Encoding = encoding ?? throw new ArgumentNullException(nameof(encoding));
+            _bytePool = bytePool ?? throw new ArgumentNullException(nameof(bytePool));
+            _charPool = charPool ?? throw new ArgumentNullException(nameof(charPool));
+            _stream = stream ?? throw new ArgumentNullException(nameof(stream));
 
-            if (bytePool == null)
-            {
-                throw new ArgumentNullException(nameof(bytePool));
-            }
-
-            if (charPool == null)
-            {
-                throw new ArgumentNullException(nameof(charPool));
-            }
-
-            _stream = stream;
-            Encoding = encoding;
             _charBufferSize = bufferSize;
 
             _encoder = encoding.GetEncoder();
-            _bytePool = bytePool;
-            _charPool = charPool;
-
             _charBuffer = charPool.Rent(bufferSize);
 
             try
diff --git a/src/Microsoft.AspNetCore.WebUtilities/breakingchanges.netcore.json b/src/Microsoft.AspNetCore.WebUtilities/breakingchanges.netcore.json
new file mode 100644
index 0000000000..c1f57ccf9f
--- /dev/null
+++ b/src/Microsoft.AspNetCore.WebUtilities/breakingchanges.netcore.json
@@ -0,0 +1,7 @@
+[
+  {
+    "TypeId": "public class Microsoft.AspNetCore.WebUtilities.HttpResponseStreamWriter : System.IO.TextWriter",
+    "MemberId": "public const System.Int32 DefaultBufferSize = 1024",
+    "Kind": "Removal"
+  }
+]
diff --git a/test/Microsoft.AspNetCore.WebUtilities.Tests/HttpResponseStreamWriterTest.cs b/test/Microsoft.AspNetCore.WebUtilities.Tests/HttpResponseStreamWriterTest.cs
index f87a6a70e6..10bd4bda3f 100644
--- a/test/Microsoft.AspNetCore.WebUtilities.Tests/HttpResponseStreamWriterTest.cs
+++ b/test/Microsoft.AspNetCore.WebUtilities.Tests/HttpResponseStreamWriterTest.cs
@@ -161,10 +161,10 @@ namespace Microsoft.AspNetCore.WebUtilities.Test
         }
 
         [Theory]
-        [InlineData(1023)]
-        [InlineData(1024)]
-        [InlineData(1050)]
-        [InlineData(2048)]
+        [InlineData(HttpResponseStreamWriter.DefaultBufferSize - 1)]
+        [InlineData(HttpResponseStreamWriter.DefaultBufferSize)]
+        [InlineData(HttpResponseStreamWriter.DefaultBufferSize + 1)]
+        [InlineData(HttpResponseStreamWriter.DefaultBufferSize * 2)]
         public async Task FlushesBuffer_ButNotStream_OnFlushAsync(int byteLength)
         {
             // Arrange