Add samples.

Samples/Shared/ObjectExtensions.cs

@@ -0,0 +1,25 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Text.Json;
+
+namespace MQTTnet.Samples.Shared;
+
+internal static class ObjectExtensions
+{
+    public static TObject DumpToConsole<TObject>(this TObject @object)
+    {
+        var output = "NULL";
+        if (@object != null)
+        {
+            output = JsonSerializer.Serialize(@object, new JsonSerializerOptions
+            {
+                WriteIndented = true
+            });
+        }
+        
+        Console.WriteLine($"[{@object?.GetType().Name}]:\r\n{output}");
+        return @object;
+    }
+}