dotnet-core/release-notes/2.1/api-diff/2.0-vs-2.1_System.Threading.Tasks.Dataflow.md

System.Threading.Tasks.Dataflow

 namespace System.Threading.Tasks.Dataflow {
-    public struct DataflowMessageHeader : IEquatable<DataflowMessageHeader>
+    public readonly struct DataflowMessageHeader : IEquatable<DataflowMessageHeader>
 }