Sending a `Null` value for parameter with Alamofire
<p>I have updated to Swift3 and the latest Alamofire '~> 4.0' 
When I try and make my parameters I now get <code>&lt;null&gt;</code> instead of <code>null</code> for settings that I do not have set. Which conflicts with my backend. </p>

<p>Is there a way to send <code>null</code>?</p>

<p>When I set the value to nil it is not included in the <code>put</code> the dictionary strips it out. But I need all values to be sent back.</p>

<p>My code </p>

<pre><code>func saveOfficeHours(days: [OfficeHours]) {
  guard let URL = LocationInfo.shared.url else {
    assertionFailure("location URL is nil")
    return
    }

  let formatter = DateFormatter()
  formatter.dateFormat = "HH:mm:ss"

  func formatTime(time: Date?) -&gt; Any {
      guard let time = time else { return NSNull() }
      return formatter.string(from: time)
  }

  var parameters: [String: Any] = [:]
  for week in days {
    parameters["\(week.day)_hours_start"] = formatTime(time: week.hoursStart)
    parameters["\(week.day)_hours_stop"] =  formatTime(time: week.hoursEnd)
    parameters["\(week.day)_lunch_hours_start"] =  formatTime(time: week.lunchStart)
    parameters["\(week.day)_lunch_hours_stop"] =  formatTime(time: week.lunchEnd)
    parameters["\(week.day)_break_hours_start"] =  formatTime(time: week.breakStart)
    parameters["\(week.day)_break_hours_stop"] =  formatTime(time: week.breakEnd)
  }

  Alamofire.request(URL, method: .put, parameters: parameters, encoding: URLEncoding.httpBody, headers: API.workstationTokenAuthHeaders()).validate().responseJSON {
    response in
    switch response.result {
    case .success:
        print("Success setting office hours")
    case .failure(let error):
        print("Failure setting office hours: \n \n -------==========-------- \n \n\(error)\n \n -------==========-------- \n")
    }
  }
}
</code></pre>

<p>Thanks for your help in advance.</p>