Enhance MessageOptions with detailed XML documentation and support for custom properties

Author: niemyjski

src/Foundatio/Messaging/IMessageBus.cs

@@ -1,16 +1,52 @@
-using System;
+using System;
 using System.Collections.Generic;
 
 namespace Foundatio.Messaging;
 
+/// <summary>
+/// Represents a message bus that supports both publishing and subscribing to messages.
+/// </summary>
 public interface IMessageBus : IMessagePublisher, IMessageSubscriber, IDisposable
 {
 }
 
-public class MessageOptions
+/// <summary>
+/// Options for configuring message publishing behavior.
+/// </summary>
+public record MessageOptions
 {
+    /// <summary>
+    /// Gets or sets a unique identifier for the message.
+    /// Can be used for message deduplication and idempotency checks.
+    /// </summary>
     public string UniqueId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the correlation identifier for distributed tracing.
+    /// If not set, this is automatically populated from <see cref="System.Diagnostics.Activity.Current"/>
+    /// when the message is published, enabling end-to-end request tracing across services.
+    /// </summary>
     public string CorrelationId { get; set; }
+
+    /// <summary>
+    /// Gets or sets the delay before the message is delivered to subscribers.
+    /// <para>
+    /// Support for delayed delivery varies by provider. Some providers support native delayed delivery
+    /// where messages are persisted and survive application restarts. Other providers use an in-memory
+    /// fallback where messages are held in memory until the delay expires.
+    /// </para>
+    /// <para>
+    /// <strong>Warning:</strong> For providers using the in-memory fallback, delayed messages are not persisted
+    /// and will be lost if the application restarts before the delay expires. Check your provider's
+    /// documentation for specific behavior.
+    /// </para>
+    /// </summary>
     public TimeSpan? DeliveryDelay { get; set; }
+
+    /// <summary>
+    /// Gets or sets custom properties to include with the message.
+    /// These properties are propagated through the message bus and available to subscribers.
+    /// The mechanism for propagation varies by provider implementation.
+    /// </summary>
     public IDictionary<string, string> Properties { get; set; } = new Dictionary<string, string>();
 }