完善客户端功能并同步差距文档

extension/tests/net_classic_session_test.cpp

@@ -871,9 +871,15 @@ int main() {
 		ex.arg1 = 27001;
 		ex.arg2 = {0, 4};
 		ex.arg3 = 7;
+		ex.sockets[1] = 9002;
+		ex.attrs[2] = {17, -33};
 		feed(s, raw(ex));
 		CHECK(s.world().exchange().self_items[4].vnum == 27001 &&
-				s.world().exchange().self_items[4].count == 7, "exchange item add");
+				s.world().exchange().self_items[4].count == 7 &&
+				s.world().exchange().self_items[4].sockets[1] == 9002 &&
+				s.world().exchange().self_items[4].attrs[2].type == 17 &&
+				s.world().exchange().self_items[4].attrs[2].value == -33,
+				"exchange item add keeps sockets/attrs");
 
 		ex.subheader = EXCHANGE_GC_GOLD_ADD;
 		ex.arg1 = 123456;