dotnet-core/release-notes/6.0/preview/api-diff/preview1/.Net/6.0-preview1_System.Runtime.CompilerServices.md

System.Runtime.CompilerServices

 namespace System.Runtime.CompilerServices {
+    public class CallConvSuppressGCTransition {
+        public CallConvSuppressGCTransition();
+    }
     public static class Unsafe {
+        public static ref T Add<T>(ref T source, UIntPtr elementOffset);
+        public static ref T AddByteOffset<T>(ref T source, UIntPtr byteOffset);
+        public static ref T Subtract<T>(ref T source, UIntPtr elementOffset);
+        public static ref T SubtractByteOffset<T>(ref T source, UIntPtr byteOffset);
     }
 }