h-next = free_list[classno];
For years, Google has explicitly told developers that API keys are safe to embed in client-side code. Firebase's own security checklist states that API keys are not secrets.
，详情可参考同城约会
要确保 package 包名声明必须与 Gradle 配置中的 package 路径完全一致，如果包名错误，Protobuf 编译器可能无法生成对应的实体类文件。
Clone a new container from a checkpoint to get identical copies:
waste some memory.