update add jsonproperty

src/DotNetCore.CAP/Infrastructure/Helper.cs

@@ -43,7 +43,7 @@ namespace DotNetCore.CAP.Infrastructure
 		public static long ToTimestamp(DateTime value)
 		{
 			var elapsedTime = value - Epoch;
-            return (long) elapsedTime.TotalSeconds;
+			return (long)elapsedTime.TotalSeconds;
 		}
 
 		public static DateTime FromTimestamp(long value)
@@ -76,7 +76,17 @@ namespace DotNetCore.CAP.Infrastructure
 		{
 			var jObj = JObject.Parse(json);
 			foreach (var property in properties)
+			{
+				if (jObj.TryGetValue(property.Key, out var _))
+				{
+					jObj[property.Key] = property.Value;
+				}
+				else
+				{
 					jObj.Add(new JProperty(property.Key, property.Value));
+				}
+			}
+
 			return jObj.ToString();
 		}