add xml comments for MessageContext.cs

dotnet/src/Microsoft.AutoGen/Contracts/PythonEquiv/MessageContext.cs

@@ -3,14 +3,38 @@
 
 namespace Microsoft.AutoGen.Contracts.Python;
 
+/// <summary>
+/// Represents the context of a message being sent within the agent runtime.
+/// This includes metadata such as the sender, topic, RPC status, and cancellation handling.
+/// </summary>
 public class MessageContext(string messageId, CancellationToken cancellationToken)
 {
+    /// <summary>
+    /// Gets or sets the unique identifier for this message.
+    /// </summary>
     public string MessageId { get; set; } = messageId;
+
+    /// <summary>
+    /// Gets or sets the cancellation token associated with this message.
+    /// This can be used to cancel the operation if necessary.
+    /// </summary>
     public CancellationToken CancellationToken { get; set; } = cancellationToken;
 
+    /// <summary>
+    /// Gets or sets the sender of the message.
+    /// If <c>null</c>, the sender is unspecified.
+    /// </summary>
     public AgentId? Sender { get; set; }
+
+    /// <summary>
+    /// Gets or sets the topic associated with the message.
+    /// If <c>null</c>, the message is not tied to a specific topic.
+    /// </summary>
     public TopicId? Topic { get; set; }
 
+    /// <summary>
+    /// Gets or sets a value indicating whether this message is part of an RPC (Remote Procedure Call).
+    /// </summary>
     public bool IsRpc { get; set; }
 }