For Swift 3.x / Swift 4.0 / Swift 5.0 users with Alamofire >= 5.0
Used request modifier to increase and decrease the timeout interval.
Alamofire's request creation methods offer the most common parameters for customization but sometimes those just aren't enough. The URLRequests created from the passed values can be modified by using a RequestModifier closure when creating requests. For example, to set the URLRequest's timeoutInterval to 120 seconds, modify the request in the closure.
var manager = Session.default
manager.request(urlString, method: method, parameters: dict, headers: headers, requestModifier: { $0.timeoutInterval = 120 }).validate().responseJSON { response in
OR
RequestModifiers also work with trailing closure syntax.
var manager = Session.default
manager.request("https://httpbin.org/get") { urlRequest in
urlRequest.timeoutInterval = 60
urlRequest.allowsConstrainedNetworkAccess = false
}
.response(...)