      - parameter requiredAuthorization: Is the request call authenticated? Default value is false
      - returns: The request headers
      */
-    class func buildRequestHeader(requiredAuthorization: Bool) -> HttpHeaders {
+    public class func buildRequestHeader(requiredAuthorization: Bool) -> HttpHeaders {
         var requestHeaders: HttpHeaders!
         if requiredAuthorization {
             requestHeaders = sharedInstance().authorizationHeaders

     - parameter error: The error object
     - returns: Return true if the request is connection timeout, false otherwise
     */
    func isConnectionTimeoutError(error: NSError) -> Bool {
        return error.domain == "NSURLErrorDomain" && error.code == -1001
    }
    

     - parameter timeoutInterval: timeout interval for network request
     - returns: The URL session configuration instance
     */
    public class func configurationWithTimeoutInterval(timeoutInterval: NSTimeInterval) -> NSURLSessionConfiguration {
        let configuration = NSURLSessionConfiguration.defaultSessionConfiguration()
        configuration.timeoutIntervalForRequest = timeoutInterval
        return configuration
