How can I check exceptions when using IOmniTaskControl/TOmniWorker?

I'm using an IOmniTaskControl/TOmniWorker to funnel code execution onto a specific thread. I'll reuse this IOmniTaskControl repeatedly for multiple Invoke calls. How do I check for exceptions that may have occurred during the Invoke? This is a follow on question to the question/answer: Waiting for Invoke to finish when using IOmniTaskControl/TOmniWorker.

I've checked the ExitCode and FatalException of the IOmniTaskControl but they are not set. It seems that the IOmniTaskControl will create a new task automatically for each Invoke call, and the exception gets placed onto that task, if it occurs. However, I have no reference to that task following the completion of the Invoke. I'm using a TOmniWaitableValue to flag when the invoke completes, but not clear on what I will need to do to make any exception that occurred available to me on return from the WaitFor(...).

Here is a snippet of the structure I have:

interface

type
  TMyTaskProc = reference to procedure;

  TMyTask = class
  private
    FWorker:      IOmniWorker;
    FTaskControl: IOmniTaskControl;
    FWaitable:    IOmniWaitableValue;
  public
    constructor Create;
    destructor Destroy; override;

    procedure AwaitInvoke(Proc: TMyTaskProc); overload;
  end;

implementation

type
  TMyTaskWorker = class(TOmniWorker);

constructor TMyTask.Create;
begin
  inherited;

  FWorker := TMyTaskWorker.Create;
  FTaskControl := CreateTask(FWorker).Run;
  FWaitable := TOmniWaitableValue.Create;
end;

destructor TMyTask.Destroy;
begin
  FTaskControl.Terminate;
  FTaskControl := nil;

  FWaitable := nil;

  inherited;
end;

procedure TMyTask.AwaitInvoke(Proc: TMyTaskProc);
begin
  FWaitable.Reset;

  FTaskControl.Invoke(
    procedure
    begin
      try
        Proc();
      finally
        FWaitable.Signal;
      end;
    end
  );

  FWaitable.WaitFor(INFINITE);
end;

So in the above setup, how can I check after FWaitable.WaitFor(INFINITE) for any exception that might have occurred during the Proc() call. I'd like to just raise it again at that point in the calling thread.

You have to catch the exception at the point when you call Proc and then somehow notify the caller of the situation. For example:

FTaskControl.Invoke(
  procedure
  var
    return: TOmniValue;
  begin
    return := TOmniValue.Null;
    try
      try
        Proc();
      except
        return.AsException := AcquireExceptionObject;
      end;
    finally
      FWaitable.Signal(return);
    end;
  end
);

FWaitable.WaitFor(INFINITE);
if FWaitable.Value.IsException then begin
  Writeln('Caught exception ' + FWaitable.Value.AsException.ClassName);
  FWaitable.Value.AsException.Free;
end;