Log "SslProtocol" after successful handshake

Author: halter73

src/Servers/Kestrel/Core/src/CoreStrings.resx

@@ -602,4 +602,7 @@ For more information on configuring HTTPS see https://go.microsoft.com/fwlink/?l
   <data name="GreaterThanOrEqualToZeroRequired" xml:space="preserve">
     <value>A value greater than or equal to zero is required.</value>
   </data>
+  <data name="HttpsConnectionEstablished" xml:space="preserve">
+    <value>Connection "{connectionId}" established using the following protocol: {protocol}</value>
+  </data>
 </root>

src/Servers/Kestrel/Core/src/Middleware/HttpsConnectionMiddleware.cs

@@ -252,6 +252,8 @@ public async Task OnConnectionAsync(ConnectionContext context)
 
             KestrelEventSource.Log.TlsHandshakeStop(context, feature);
 
+            _logger.LogDebug(3, CoreStrings.HttpsConnectionEstablished, context.ConnectionId, sslStream.SslProtocol);
+
             var originalTransport = context.Transport;
 
             try