Append when the GeoFeed is retrieved and if it was generated from in memory cache

AS1024.GeoFeed.Core/Tools/GeoFeedTools.cs

@@ -5,10 +5,23 @@ namespace AS1024.GeoFeed.Core.Tools
 {
     public static class GeoFeedTools
     {
-        public static string ToGeoFeedCsv(this List<IPGeoFeed> geoFeeds)
+        /// <summary>
+        /// Returns a CSV string for a given GeoFeed retreived from various sources
+        /// </summary>
+        /// <param name="geoFeeds">GeoFeed returned from the source of truth</param>
+        /// <param name="timeStamp">If a timestamp should be appended at the header</param>
+        /// <param name="isCached">If the result is cached</param>
+        /// <returns></returns>
+        public static string ToGeoFeedCsv(this List<IPGeoFeed> geoFeeds, bool timeStamp = false, bool isCached = false)
         {
             StringBuilder csvContent = new();
 
+            if (timeStamp)
+                csvContent.AppendLine($"# GeoFeed generated on {DateTime.UtcNow:R}");
+
+            if (isCached)
+                csvContent.AppendLine($"# Geofeed data is returned from local in memory cache");
+
             foreach (IPGeoFeed feed in geoFeeds)
             {
                 csvContent.AppendLine($"{feed.Prefix},{feed.GeolocCountry},{feed.GeolocRegion},{feed.GeolocCity},{feed.GeolocPostalCode}");