In Delphi to "async/await". Use "TTask"

async_await.pas

procedure TForm1.Button1Click(Sender: TObject);
var
  http: TIdHTTP;
begin
  FstTest := TTask.Future<String>(function():String begin
    Sleep(3000);
    http  := TIdHTTP.Create();
    try
      Result := http.Get('http://www.mojeld.com/');
    finally
      http.DisposeOf;
    end;
  end);
  //Memo1.Lines.Text  := FstTest.Value;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  Memo1.Lines.Text  := FstTest.Value;
end;

I try:
procedure TForm1.Button1Click(Sender: TObject);
var
LFuture: IFuture;
begin
mmoLog.Lines.Add(Format('Start!', []));

LFuture := TTask.Future(
function(): String
begin
Sleep(3000);

  Result := 'I''m Future.';
end
);

mmoLog.Lines.Add(LFuture.Value);

mmoLog.Lines.Add(Format('End!', []));
end;

Output:
Start!
I'm Future.
End!

Output is OK.
But UI is blocked.