Fix NullRef when RPC result is a nullable TL type

.github/dev.yml

@@ -2,7 +2,7 @@ pr: none
 trigger:
 - master
 
-name: 2.3.1-dev.$(Rev:r)
+name: 2.3.2-dev.$(Rev:r)
 
 pool:
   vmImage: ubuntu-latest

EXAMPLES.md

@@ -352,12 +352,15 @@ client.TcpHandler = async (address, port) =>
 };
 ```
 <a name="mtproxy"></a>
-MTProxy (MTProto proxy) can be used to prevent ISP blocks, through the `client.MTProxyUrl` property:
+MTProxy (MTProto proxy) can be used to prevent ISP blocking Telegram servers, through the `client.MTProxyUrl` property:
 ```csharp
 using var client = new WTelegram.Client(Environment.GetEnvironmentVariable);
 client.MTProxyUrl = "http://t.me/proxy?server=...&port=...&secret=...";
 var myself = await client.LoginUserIfNeeded();
 ```
+You can find a list of working MTProxies in channels like [@ProxyMTProto](https://t.me/ProxyMTProto) or [@MTProxyT](https://t.me/MTProxyT) *(right-click the "Connect" buttons)*  
+If your Telegram client is already connected to such MTPROTO proxy, you can also export its URL by clicking on the shield button ![🛡](https://raw.githubusercontent.com/telegramdesktop/tdesktop/dev/Telegram/Resources/icons/proxy_on.png) and then **⋮** > **Share**
+
 *Note: WTelegramClient always uses transport obfuscation when connecting to Telegram servers, even without MTProxy*
 
 <a name="logging"></a>

README.md

@@ -7,10 +7,11 @@
 
 ## _Telegram Client API library written 100% in C# and .NET Standard_
 
-This ReadMe is a **quick but important tutorial** to learn the fundamentals about this library. Please read it all.  
 This library allows you to connect to Telegram and control a user programmatically (or a bot, but [Telegram.Bot](https://github.com/TelegramBots/Telegram.Bot) is much easier for that).
 All the Telegram Client APIs are supported so you can do everything the user could do with a full Telegram GUI client.
 
+This ReadMe is a **quick but important tutorial** to learn the fundamentals about this library. Please read it all.
+
 >⚠️ This library relies on asynchronous C# programming (`async/await`) so make sure you are familiar with this advanced topic before proceeding.  
 >If you are a beginner in C#, starting a project based on this library might not be a great idea.
 

src/Client.cs

@@ -1109,6 +1109,7 @@ namespace WTelegram
 			var result = await rpc.Task;
 			switch (result)
 			{
+				case null: return default;
 				case T resultT: return resultT;
 				case RpcError { error_code: var code, error_message: var message }:
 					int x = -1;