+ explicit CheckerSide(int sockfd) : channel_(sockfd) {}
+
+ // No copy:
+ CheckerSide(CheckerSide const&) = delete;
+ CheckerSide& operator=(CheckerSide const&) = delete;
+ CheckerSide& operator=(CheckerSide&&) = delete;
+
+ Channel const& get_channel() const { return channel_; }
+ Channel& get_channel() { return channel_; }