procedure MustExecInMainThread(out Result: ISuperObject); // Sorry, the parameter cannot be changed
var
  SwitchThread: Boolean;
begin
  SwitchThread := Windows.GetCurrentThreadId <> MainThreadID;
  if SwitchThread then
    EnterMainThread;
  try
    ExecAndReturnResultsAsOutParam(Result);
  finally
    if SwitchThread then
      LeaveMainThread;
  end;
end;

procedure MustExecInMainThread(out Result: ISuperObject);
var
  ResultTemp: ISuperObject;
begin
  TAsyncCalls.VCLSync(procedure
  begin
    ExecAndReturnResultsAsOutParam(ResultTemp);
  end);
  Result := ResultTemp;
end;

procedure MustExecInMainThread(out Result: ISuperObject); // Sorry, the parameter cannot be changed
var
  SwitchThread: Boolean;
  ResultTemp: ISuperObject;
begin
  SwitchThread := Windows.GetCurrentThreadId <> MainThreadID;
  if SwitchThread then begin
    TThread.Synchronize(nil,
      procedure
      begin
        ExecAndReturnResultsAsOutParam(ResultTemp);
      end
    )
    Result := ResultTemp;
  end
  else
    ExecAndReturnResultsAsOutParam(Result);
end;

TAsyncCalls.VCLInvoke(
    procedure
    begin
      DoVCLStuffHere
    end)