Add articles on logging and progress (#717)

* Add articles on logging and progress
* Address comments in PR review

docs/concepts/logging/samples/client/LoggingClient.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="ModelContextProtocol.Core" Version="0.3.0-preview.3" />
+  </ItemGroup>
+
+</Project>

docs/concepts/logging/samples/client/Program.cs

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+using ModelContextProtocol.Protocol;
+using ModelContextProtocol.Client;
+using System.Text.Json;
+
+var endpoint = Environment.GetEnvironmentVariable("ENDPOINT") ?? "http://localhost:3001";
+
+var clientTransport = new SseClientTransport(new()
+{
+    Endpoint = new Uri(endpoint),
+    TransportMode = HttpTransportMode.StreamableHttp,
+});
+
+await using var mcpClient = await McpClientFactory.CreateAsync(clientTransport);
+
+// <snippet_LoggingCapabilities>
+// Verify that the server supports logging
+if (mcpClient.ServerCapabilities.Logging is null)
+{
+    Console.WriteLine("Server does not support logging.");
+    return;
+}
+// </snippet_LoggingCapabilities>
+
+// Get the first argument if it was specified
+var firstArgument = args.Length > 0 ? args[0] : null;
+
+if (firstArgument is not null)
+{
+    // Set the logging level to the value from the first argument
+    if (Enum.TryParse<LoggingLevel>(firstArgument, true, out var loggingLevel))
+    {
+        // <snippet_LoggingLevel>
+        await mcpClient.SetLoggingLevel(loggingLevel);
+        // </snippet_LoggingLevel>
+    }
+    else
+    {
+        Console.WriteLine($"Invalid logging level: {firstArgument}");
+        // Print a list of valid logging levels
+        Console.WriteLine("Valid logging levels are:");
+        foreach (var level in Enum.GetValues<LoggingLevel>())
+        {
+            Console.WriteLine($" - {level}");
+        }
+    }
+}
+
+// <snippet_LoggingHandler>
+mcpClient.RegisterNotificationHandler(NotificationMethods.LoggingMessageNotification,
+    (notification, ct) =>
+    {
+        if (JsonSerializer.Deserialize<LoggingMessageNotificationParams>(notification.Params) is { } ln)
+        {
+            Console.WriteLine($"[{ln.Level}] {ln.Logger} {ln.Data}");
+        }
+        else
+        {
+            Console.WriteLine($"Received unexpected logging notification: {notification.Params}");
+        }
+
+        return default;
+    });
+// </snippet_LoggingHandler>
+
+// Now call the "logging_tool" tool
+await mcpClient.CallToolAsync("logging_tool");
+