feat(ProtoBuffServerHelper): 为操作码信息添加Clear方法实现

当操作码信息有父类时，自动生成Clear方法用于清空字段值。对于重复字段和键值对字段使用Clear()，其他字段设置为默认值。

Author: AlianBlank

ProtoExport/ProtoBuffServerHelper.cs

@@ -107,7 +107,40 @@ public void Run(MessageInfoList messageInfoList, string outputPath, string names
                         }
                     }
 
-                    sb.AppendLine("    }");
+                    if (!string.IsNullOrEmpty(operationCodeInfo.ParentClass))
+                    {
+                        sb.AppendLine();
+                        sb.AppendLine("\t\tpublic override void Clear()");
+                        sb.AppendLine("\t\t{");
+                        for (var index = 0; index < operationCodeInfo.Fields.Count; index++)
+                        {
+                            var operationField = operationCodeInfo.Fields[index];
+                            if (!operationField.IsValid)
+                            {
+                                continue;
+                            }
+
+                            if (operationField.IsRepeated)
+                            {
+                                sb.AppendLine($"\t\t\t{operationField.Name}.Clear();");
+                            }
+                            else
+                            {
+                                if (operationField.IsKv)
+                                {
+                                    sb.AppendLine($"\t\t\t{operationField.Name}.Clear();");
+                                }
+                                else
+                                {
+                                    sb.AppendLine($"\t\t\t{operationField.Name} = default;");
+                                }
+                            }
+                        }
+
+                        sb.AppendLine("\t\t}");
+                    }
+
+                    sb.AppendLine("\t}");
                     sb.AppendLine();
                 }
             }