Replace `?? CancellationToken.None` pattern with the simpler `default`

src/BizHawk.Client.Common/Api/ClientWebSocketWrapper.cs

@@ -14,52 +14,67 @@ namespace BizHawk.Client.Common
 		/// <summary>calls <see cref="ClientWebSocket.State"/> getter (unless closed/disposed, then <see cref="WebSocketState.Closed"/> is always returned)</summary>
 		public WebSocketState State => _w?.State ?? WebSocketState.Closed;
 
-		public ClientWebSocketWrapper(Uri uri, CancellationToken? cancellationToken = null)
+		public ClientWebSocketWrapper(
+			Uri uri,
+			CancellationToken cancellationToken = default/* == CancellationToken.None */)
 		{
-			cancellationToken ??= CancellationToken.None;
 			_w = new ClientWebSocket();
-			_w.ConnectAsync(uri, cancellationToken.Value).Wait(cancellationToken.Value);
+			_w.ConnectAsync(uri, cancellationToken).Wait(cancellationToken);
 		}
 
 		/// <summary>calls <see cref="ClientWebSocket.CloseAsync"/></summary>
 		/// <remarks>also calls <see cref="ClientWebSocket.Dispose"/> (wrapper property <see cref="State"/> will continue to work, method calls will throw <see cref="ObjectDisposedException"/>)</remarks>
-		public Task Close(WebSocketCloseStatus closeStatus, string statusDescription, CancellationToken? cancellationToken = null)
+		public Task Close(
+			WebSocketCloseStatus closeStatus,
+			string statusDescription,
+			CancellationToken cancellationToken = default/* == CancellationToken.None */)
 		{
 			if (_w == null) throw new ObjectDisposedException(nameof(_w));
-			var task = _w.CloseAsync(closeStatus, statusDescription, cancellationToken ?? CancellationToken.None);
+			var task = _w.CloseAsync(closeStatus, statusDescription, cancellationToken);
 			_w.Dispose();
 			_w = null;
 			return task;
 		}
 
 		/// <summary>calls <see cref="ClientWebSocket.ReceiveAsync"/></summary>
-		public Task<WebSocketReceiveResult> Receive(ArraySegment<byte> buffer, CancellationToken? cancellationToken = null)
+		public Task<WebSocketReceiveResult> Receive(
-			=> _w?.ReceiveAsync(buffer, cancellationToken ?? CancellationToken.None)
+			ArraySegment<byte> buffer,
-				?? throw new ObjectDisposedException(nameof(_w));
+			CancellationToken cancellationToken = default/* == CancellationToken.None */)
+				=> _w?.ReceiveAsync(buffer, cancellationToken)
+					?? throw new ObjectDisposedException(nameof(_w));
 
 		/// <summary>calls <see cref="ClientWebSocket.ReceiveAsync"/></summary>
-		public string Receive(int bufferCap, CancellationToken? cancellationToken = null)
+		public string Receive(
+			int bufferCap,
+			CancellationToken cancellationToken = default/* == CancellationToken.None */)
 		{
 			if (_w == null) throw new ObjectDisposedException(nameof(_w));
 			var buffer = new byte[bufferCap];
-			var result = Receive(new ArraySegment<byte>(buffer), cancellationToken ?? CancellationToken.None).Result;
+			var result = Receive(new ArraySegment<byte>(buffer), cancellationToken).Result;
 			return Encoding.UTF8.GetString(buffer, 0, result.Count);
 		}
 
 		/// <summary>calls <see cref="ClientWebSocket.SendAsync"/></summary>
-		public Task Send(ArraySegment<byte> buffer, WebSocketMessageType messageType, bool endOfMessage, CancellationToken? cancellationToken = null)
+		public Task Send(
-			=> _w?.SendAsync(buffer, messageType, endOfMessage, cancellationToken ?? CancellationToken.None)
+			ArraySegment<byte> buffer,
-				?? throw new ObjectDisposedException(nameof(_w));
+			WebSocketMessageType messageType,
+			bool endOfMessage,
+			CancellationToken cancellationToken = default/* == CancellationToken.None */)
+				=> _w?.SendAsync(buffer, messageType, endOfMessage, cancellationToken)
+					?? throw new ObjectDisposedException(nameof(_w));
 
 		/// <summary>calls <see cref="ClientWebSocket.SendAsync"/></summary>
-		public Task Send(string message, bool endOfMessage, CancellationToken? cancellationToken = null)
+		public Task Send(
+			string message,
+			bool endOfMessage,
+			CancellationToken cancellationToken = default/* == CancellationToken.None */)
 		{
 			if (_w == null) throw new ObjectDisposedException(nameof(_w));
 			return Send(
 				new ArraySegment<byte>(Encoding.UTF8.GetBytes(message)),
 				WebSocketMessageType.Text,
 				endOfMessage,
-				cancellationToken ?? CancellationToken.None
+				cancellationToken
 			);
 		}
 	}

src/BizHawk.Client.Common/Api/WebSocketServer.cs

@@ -6,6 +6,9 @@ namespace BizHawk.Client.Common
 {
 	public sealed class WebSocketServer
 	{
-		public ClientWebSocketWrapper Open(Uri uri, CancellationToken? cancellationToken = null) => new ClientWebSocketWrapper(uri, cancellationToken);
+		public ClientWebSocketWrapper Open(
+			Uri uri,
+			CancellationToken cancellationToken = default/* == CancellationToken.None */)
+				=> new(uri, cancellationToken);
 	}
 }