https://developer.apple.com/library/content/documentation/NetworkingInternetWeb/Conceptual/NetworkingOverview/CommonPitfalls/CommonPitfalls.html#//apple_ref/doc/uid/TP40010220-CH4-SW1
iOS 记得
signal(SIGPIPE, SIG_IGN);
or
int value = 1; setsockopt(sock, SOL_SOCKET, SO_NOSIGPIPE, &value, sizeof(value));