doc: live query

LiveQuery/LiveQuery/Public/LCLiveQuery.cs

@@ -10,7 +10,7 @@ using LeanCloud.LiveQuery.Internal;
 
 namespace LeanCloud.LiveQuery {
     /// <summary>
-    /// LiveQuery
+    /// LCLiveQuery provides the live query in LeanCloud.
     /// </summary>
     public class LCLiveQuery {
         /// <summary>

LiveQuery/LiveQuery/Public/LCQueryExtension.cs

@@ -2,7 +2,15 @@
 using LeanCloud.Storage;
 
 namespace LeanCloud.LiveQuery {
+    /// <summary>
+    /// LCQueryExtension is the extension of query for live query.
+    /// </summary>
     public static class LCQueryExtension {
+        /// <summary>
+        /// Subscribes this LCQuery to live query.
+        /// </summary>
+        /// <param name="query"></param>
+        /// <returns></returns>
         public static async Task<LCLiveQuery> Subscribe(this LCQuery query) {
             LCLiveQuery liveQuery = new LCLiveQuery {
                 Query = query