dotnet-core/release-notes/3.0/api-diff/.Net/3.0.0_System.Net.WebSockets.md

System.Net.WebSockets

 namespace System.Net.WebSockets {
     public sealed class ClientWebSocket : WebSocket {
+        public override ValueTask<ValueWebSocketReceiveResult> ReceiveAsync(Memory<byte> buffer, CancellationToken cancellationToken);
+        public override ValueTask SendAsync(ReadOnlyMemory<byte> buffer, WebSocketMessageType messageType, bool endOfMessage, CancellationToken cancellationToken);
     }
 }