URLSessionExtensionFullImplementation.swift

extension URLSession {
  class func initSwizzle() throws {
    typealias ResultBlock = (@escaping ([URLSessionTask]) -> Void) -> Void
        
    let original = #selector((URLSession.getAllTasks(completionHandler:)) as (URLSession) -> ResultBlock)
    let swizzled = #selector((FakeURLSession._getAllTasks(completionHandler:)) as (FakeURLSession) -> ResultBlock)

    guard
      let originalMethod = class_getInstanceMethod(URLSession.self, original),
      let swizzledMethod = class_getInstanceMethod(FakeURLSession.self, swizzled)
      else { return }

    method_exchangeImplementations(originalMethod, swizzledMethod)
  }
}