 */
 public struct Request {
     
-    // MARK: HTTP Methods
+    // MARK: Supported HTTP Methods
 
     public enum Method: String {
         case GET = "GET"

        }
    }
    
    // MARK: HTTP Headers
    
    public struct Headers {
        public static let userAgent = "User-Agent"

        public static let cacheControl = "Cache-Control"
    }
    
    // MARK: Content Type Constants
    
    public struct ContentType {
        public static let formEncoded = "application/x-www-form-urlencoded"
        public static let json = "application/json"
    }
    
    // MARK: Request Properties
    
    public let method: Method
    public let url: String
    public var parameters = [String : AnyObject]()
    public var headers = [String : String]()
    public var parameterEncoding = ParameterEncoding.Percent {
        didSet {
            if parameterEncoding == .JSON {
                contentType = ContentType.json
            }
        }
    }
    
    public var contentType: String? {
        set { headers[Headers.contentType] = newValue }
