How to use Pipeline pattern in Delphi
<p>I am trying to implement a Pipeline pattern in my test project (<a href="https://stackoverflow.com/questions/39096452/">How to make a Mutlithreded idhttp calls to do work on a StringList</a>), but am having a struggle adapting <code>TThread</code> code to Pipeline pattern code.  There are not many resources about how to use it.</p>

<p>I tried my best below, please DO NOT downvote, I know my code is messy but I'll edit my question if needed.</p>

<pre><code>type
  TForm2 = class(TForm)
    ...
  private
    procedure Retriever(const input: TOmniValue; var output: TOmniValue);
    procedure Inserter(const input, output: IOmniBlockingCollection);
    function HttpGet(url: string; var page: string): boolean;
  end;

procedure TForm2.startButton1Click(Sender: TObject);
var
  pipeline: IOmniPipeline;
  i       : Integer;
  v       : TOmniValue;
  s       : string;
  urlList : TStringList;
begin
  pipeline := Parallel.Pipeline;
  pipeline.Stage(Retriever);
  pipeline.Stage(Inserter).NumTasks(10);
  pipeline.Run;
  for s in urlList do
    pipeline.Input.Add(s);
  pipeline.Input.CompleteAdding;
  // wait for pipeline to complete
  pipeline.WaitFor(INFINITE);
end;

function TForm2.HttpGet(url: string; var page: string): boolean;
var
  lHTTP: TIdHTTP;
  i : integer;
  X : Tstrings;
  S,M,fPath : String;
begin
  lHTTP := TIdHTTP.Create(nil);
  X := TStringList.Create;
  try
    X.Text := lHTTP.Get('https://instagram.com/'+fPath);
    S:= ExtractDelimitedString(X.Text);
    X.Clear;
    Memo2.Lines.Add(fPath+ ' :     '+ M ); //how to pass the result to Inserter
  finally
    lHttp.Free;
  end;
end;

procedure TForm2.Inserter(const input, output: IOmniBlockingCollection);
var
  result   : TOmniValue;
  lpage     : string;
begin
  for result in input do begin
    Memo2.Lines.Add(lpage);
    FreeAndNil(lpage);
  end;
  // correect?
end;

procedure TForm2.Retriever(const input: TOmniValue; var output: TOmniValue);
var
  pageContents: string;
begin
  if HttpGet(input.AsString, pageContents) then
    output := //???
end;
</code></pre>