add xml comments for ISubscriptionDefinition.cs

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

@@ -5,16 +5,49 @@ using System.Diagnostics.CodeAnalysis;
 
 namespace Microsoft.AutoGen.Contracts.Python;
 
+/// <summary>
+/// Defines a subscription that matches topics and maps them to agents.
+/// </summary>
 public interface ISubscriptionDefinition
 {
+    /// <summary>
+    /// Gets the unique identifier of the subscription.
+    /// </summary>
     public string Id { get; }
 
+    /// <summary>
+    /// Determines whether the specified object is equal to the current subscription.
+    /// </summary>
+    /// <param name="obj">The object to compare with the current instance.</param>
+    /// <returns><c>true</c> if the specified object is equal to this instance; otherwise, <c>false</c>.</returns>
     public bool Equals([NotNullWhen(true)] object? obj) => obj is ISubscriptionDefinition other && Equals(other);
+    
+    /// <summary>
+    /// Determines whether the specified subscription is equal to the current subscription.
+    /// </summary>
+    /// <param name="other">The subscription to compare.</param>
+    /// <returns><c>true</c> if the subscriptions are equal; otherwise, <c>false</c>.</returns>
     public bool Equals(ISubscriptionDefinition? other) => Id == other?.Id;
 
+    /// <summary>
+    /// Returns a hash code for this subscription.
+    /// </summary>
+    /// <returns>A hash code for the subscription.</returns>
     public int GetHashCode() => Id.GetHashCode();
 
+    /// <summary>
+    /// Checks if a given <see cref="TopicId"/> matches the subscription.
+    /// </summary>
+    /// <param name="topic">The topic to check.</param>
+    /// <returns><c>true</c> if the topic matches the subscription; otherwise, <c>false</c>.</returns>
     public bool Matches(TopicId topic);
+
+    /// <summary>
+    /// Maps a <see cref="TopicId"/> to an <see cref="AgentId"/>.
+    /// Should only be called if <see cref="Matches"/> returns <c>true</c>.
+    /// </summary>
+    /// <param name="topic">The topic to map.</param>
+    /// <returns>The <see cref="AgentId"/> that should handle the topic.</returns>
     public AgentId MapToAgent(TopicId topic);
 }