/// Execution
extension RestCall {

    /**
     This method execute and return the task back, developper can use the task ref to cancel it, pause it, resume it back...

     - Remark: The result back to the user on main thread
     - Parameter session: **URLSession** the connection that will create the task that will be performed
     - Parameter completion: **Result** The result of the execution an enum <success, fail>.
     - Returns: The URLSessionDataTask to be executed
     */
    @discardableResult /// supress warning in unused result ...
    func execute(_ session :URLSession, completion: @escaping (Result<T,GenericError>) -> Void) -> URLSessionDataTask? {

        /// it all about the url !
        /// the map that will guide data through it's journey
        if isMalformed {
           /// Result.failure(error) => return nil
        }

        /// build the request with suitable params
        do {
            var request = try RequestBuilder.build(self)


            /// in case the call require interception of the header for additional config u can use a CallInterceptor
            self.callInterceptor.intercept(&request)

            /// create dataTask using a session object (might be custom)
            /// prepare the mission
            /// dear data, ride this task and go to the back end, ask him for data exchange, u can do it. blessed, see u soon.
            let task = session.dataTask(with: request, completionHandler: { data, response, error in
                /** handle response
                it might be a : Result.failure(error) => return nil
                or : Result.success(T)
                */

            })

            /// maybe u need (task ref) in some cases
            /// Open the pipe & Start The mission
            /// see u soon request
            /// u can do it ;)
            task.resume()

            return task
        }
        catch (let error as GenericError){
            /// Result.failure(error)
            return nil
        }
        catch{
            /// Result.failure(error)
            return nil
        }
    }

    /**
     This method mock Rest Call from json files

     - Remark: The result back to the user on main thread
     - Parameter fileName: **String** the file that contains mock data
     - Parameter completion: **Result** The result of the execution an enum <success, fail>.
     */
    func mock(_ fileName : String, completion: @escaping (Result<T,GenericError>) -> Void){
        if let path = Bundle.main.path(forResource: fileName, ofType: "json") {
            do {
                let data = try Data(contentsOf: URL(fileURLWithPath: path), options: .mappedIfSafe)
                do {
                    /** handle response
                    it might be a : Result.failure(error)
                    or : Result.success(T)
                    */
                }
            } catch {
                /// File content Cant be seen as Data
                /// Result.failure(error)
            }
        }else {
            /// File Not Found
            /// Result.failure(error)
        }
    }

}