前端：

1、优化消息排序逻辑
2、新增加载历史消息
3、修复已知问题
后端：
1、优化消息排序逻辑
2、增加用户信息缓存机制
3、修改日期类型为DateTimeOffset改善时区信息丢失问题
3、修复了已知问题
数据库：
1、新增SequenceId字段用于消息排序
2、新增ClientMsgId字段用于客户端消息回执

backend/IM_API/Services/FriendService.cs

@@ -132,8 +132,8 @@ namespace IM_API.Services
                     await _endpoint.Publish(new FriendAddEvent()
                     {
                         AggregateId = friendRequest.Id.ToString(),
-                        OccurredAt = DateTime.UtcNow,
-                        Created = DateTime.UtcNow,
+                        OccurredAt = DateTime.Now,
+                        Created = DateTime.Now,
                         EventId = Guid.NewGuid(),
                         OperatorId = friendRequest.ResponseUser,
                         RequestInfo = _mapper.Map<FriendRequestDto>(friendRequest),
@@ -183,7 +183,7 @@ namespace IM_API.Services
             await _endpoint.Publish(new RequestFriendEvent()
             {
                 AggregateId = friendRequst.Id.ToString(),
-                OccurredAt = friendRequst.Created,
+                OccurredAt = friendRequst.Created.UtcDateTime,
                 Description = friendRequst.Description,
                 EventId = Guid.NewGuid(),
                 FromUserId = friendRequst.RequestUser,
@@ -205,7 +205,7 @@ namespace IM_API.Services
                 Friend friendA = new Friend()
                 {
                     Avatar = userbInfo.Avatar,
-                    Created = DateTime.UtcNow,
+                    Created = DateTime.Now,
                     FriendId = userbInfo.Id,
                     RemarkName = remarkName ?? userbInfo.NickName,
                     StatusEnum = FriendStatus.Added,