dotnet-core/release-notes/5.0/netstandard2.1/5.0-preview5_System.Net.NetworkInformation.md

System.Net.NetworkInformation

 namespace System.Net.NetworkInformation {
-    public static class NetworkChange {
+    public class NetworkChange {
+        public NetworkChange();
+        public static void RegisterNetworkChange(NetworkChange nc);
     }
     public class PhysicalAddress {
+        public static PhysicalAddress Parse(ReadOnlySpan<char> address);
+        public static bool TryParse(ReadOnlySpan<char> address, out PhysicalAddress value);
+        public static bool TryParse(string address, out PhysicalAddress value);
     }
 }