接上篇:https://blog.csdn.net/da_ma_dai/article/details/131878516 代码节点:https://gitee.com/bobidali/lite-rx-java/commit/05199792ce75a80147c822336b46837f09229e46 java 类型转换 kt 类型: Any == Object 泛型: 协变: out T == ? extends T 逆变: in T == ? super T