One function that prints the system call and the error details and then exits with error code 1. Non-zero meaning things didn't go well. */

One function that prints the system call and the error details and then exits with error code 1. Non-zero meaning things didn't go well. */

Must be called by corresponding thread.

\brief Query if the task result is complete. Awaiting a task that is ready will not block.

不断接收字节流并打印到stdout

将键盘输入发送给对方

value_type = std::string_view reference = std::string_view&&