spdy_test_async.swift

import Foundation

let url = NSURL(string: "https://spdy.today/spdy.json")
let request = NSURLRequest(URL: url)

NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.currentQueue()) {
    _, data, _ in
    if data {
        let str = NSString(data: data, encoding: NSUTF8StringEncoding)
        println(str)
    }
}

spdy_test_sync.swift

import Foundation

let url = NSURL(string: "https://spdy.today/spdy.json")
let request = NSURLRequest(URL: url)

let data = NSURLConnection.sendSynchronousRequest(request, returningResponse: nil, error: nil)
if data {
    let str = NSString(data: data, encoding: NSUTF8StringEncoding)
    println(str)
}