httpBodyIsNotSentToTheDomainThatReceivedCookie.swift

import Dispatch
import Foundation

var setCookieRequest = URLRequest(url: URL(string: "http://httpbin.org/cookies/set?freeform=test")!)
let setCookieTask = URLSession.shared.dataTask(with: setCookieRequest) { _, _, error in
    guard error == nil else { fatalError("failed to set cookie!") }

    var request = URLRequest(url: URL(string: "http://httpbin.org/post")!)
    request.httpMethod = "POST"
    request.httpBody = "{\"key\":\"value\"}".data(using: .utf8)
    request.setValue("application/json", forHTTPHeaderField: "Content-Type")

    print("request.httpBody: \(String(describing: request.httpBody))")
    let postTask = URLSession.shared.dataTask(with: request) { data, response, error in
        print("-- response body begin")
        print(data.flatMap { String(data: $0, encoding: .utf8) } ?? "nil")
        print("-- response body end")
        exit(0)
    }
    print("postTask.originalRequest.httpBody: \(String(describing: postTask.originalRequest?.httpBody))")
    postTask.resume()
}
setCookieTask.resume()
dispatchMain()