新增私聊相关

Hotfix/Social/Mail/Helper/MailConversationHelper.cs

@@ -0,0 +1,38 @@
+using Fantasy;
+using Fantasy.Async;
+using NB.Game;
+
+namespace NB.Chat;
+
+public static class MailConversationHelper
+{
+    /// <summary>
+    /// 从数据库中读取GameAccount
+    /// </summary>
+    /// <param name="scene"></param>
+    /// <param name="firstId"></param>
+    /// <param name="secondId"></param>
+    /// <returns></returns>
+    public static async FTask<MailConversation> LoadDataBase(Scene scene, long firstId, long secondId)
+    {
+        var conversation =
+            await scene.World.DataBase.First<MailConversation>(d => d.FirstId == firstId && d.SecondId == secondId);
+        if (conversation == null)
+        {
+            return null;
+        }
+
+        conversation.Deserialize(scene);
+        return conversation;
+    }
+    
+    /// <summary>
+    /// 从数据库中移除
+    /// </summary>
+    /// <param name="scene"></param>
+    /// <param name="id"></param>
+    public static async FTask DeleteDataBase(Scene scene,long id)
+    {
+        await scene.World.DataBase.Remove<MailConversation>(id);
+    }
+}