use arrivalUnixTime for SectionDate; a TODO

Yep/Realm/Models.swift

@@ -408,7 +408,8 @@ func tryCreateSectionDateMessageInConversation(conversation: Conversation, befor
             let newSectionDateMessage = Message()
             newSectionDateMessage.conversation = conversation
             newSectionDateMessage.mediaType = MessageMediaType.SectionDate.rawValue
-            newSectionDateMessage.createdUnixTime = message.createdUnixTime - 1 // 比新消息早一秒
+            newSectionDateMessage.createdUnixTime = message.createdUnixTime - 0.001 // 比新消息早一点点即可
+            newSectionDateMessage.arrivalUnixTime = message.arrivalUnixTime - 0.001 // 比新消息早一点点即可
             newSectionDateMessage.messageID = "sectionDate-\(newSectionDateMessage.createdUnixTime)"
 
             success(newSectionDateMessage)

Yep/Services/YepServiceSync.swift

@@ -867,6 +867,9 @@ func syncMessageWithMessageInfo(messageInfo: JSONDictionary, inRealm realm: Real
                 newMessage.createdUnixTime = updatedUnixTime
             }
 
+            // TODO: 可能可以根据是否已进入Conversation界面来修改到达时间，减少聊天界面的插入切换
+            // 之后消息以到达时间排序
+
             realm.write {
                 realm.add(newMessage)
             }