Reduce network delays for your app

9:28 - Fast open with TCP handshake

/* Allow fast open on the connection parameters */
parameters.allowFastOpen = true

let connection = NWConnection(to: endpoint, using: parameters)

/* Call send with idempotent initial data before starting the connection */
connection.send(content: initialData, completion: .idempotent)
connection.start(queue: myQueue)

11:01 - Sockets with fast open

connectx(fd, ..., CONNECT_DATA_IDEMPOTENT | CONNECT_RESUME_ON_READ_WRITE, ...); // delay SYN
write(fd, ...); // SYN goes out with first data segment

13:35 - Save round-trips when switching networks with Multipath TCP

// Multipath TCP
// Save multiple round-trips when switching networks

// On URLSessionConfiguration
let configuration = URLSessionConfiguration.default
configuration.multipathServiceType = .interactive

// On NWParameters
let parameters = NWParameters.tcp
parameters.multipathServiceType = .interactive

20:09 - Background service type, App in foreground

//Use default  URLSession, set background on URLRequest
var request = URLRequest(url: myurl)
request.networkServiceType = .background

//Set service class on parameters to apply to the  NWConnection
let parameters = NWParameters.tls
parameters.serviceClass = .background

20:10 - Time insensitive tasks running in background

//Configure background URL Session

lazy var urlSession: URLSession = {
    let configuration = URLSessionConfiguration.background(withIdentifier: "MySession")
    configuration.isDiscretionary = true
    return URLSession(configuration: configuration, delegate: self, delegateQueue: nil)
}()