tweak key generator

Author: pwelter34

src/Serilog.Sinks.AzureTableStorage/Sinks/AzureTableStorage/DefaultKeyGenerator.cs

@@ -24,16 +24,16 @@ public virtual string GeneratePartitionKey(LogEvent logEvent)
     }
 
     /// <summary>
-    /// Automatically generates the RowKey using the timestamp
+    /// Automatically generates the RowKey using the timestamp 
     /// </summary>
     /// <param name="logEvent">the log event</param>
     /// <returns>The generated RowKey</returns>
     public virtual string GenerateRowKey(LogEvent logEvent)
     {
         var utcEventTime = logEvent.Timestamp.UtcDateTime;
 
-        // use time based object id to create key
-        return ObjectId.GenerateNewId(utcEventTime).ToString();
+        // create a 19 character String for reverse chronological ordering.
+        return $"{DateTime.MaxValue.Ticks - utcEventTime.Ticks:D19}";
     }