21. [stream setProperty:NSStreamNetworkServiceTypeVoIP
forKey:NSStreamNetworkServiceType];

22. [[UIApplication sharedApplication]
setKeepAliveTimeout:600
handler:^{ // }];

23. [[UIApplication sharedApplication]
setKeepAliveTimeout:600
handler:^{ // }];

24. [[UIApplication sharedApplication]
setKeepAliveTimeout:600
handler:^{ // }];

27. int fd = socket(AF_INET, SOCK_STREAM, 0);
NSInputStream* stream;
CFStreamCreatePairWithSocket(
kCFAllocatorDefault, fd,
(CFReadStreamRef*)&stream, NULL
);

28. int fd = socket(AF_INET, SOCK_STREAM, 0);
NSInputStream* stream;
CFStreamCreatePairWithSocket(
kCFAllocatorDefault, fd,
(CFReadStreamRef*)&stream, NULL
);