Extendscript render finished event

I'm running extendscript that automatically creates video than renders it

app.encoder.launchEncoder();
app.encoder.encodeSequence(sequence, out, epr, 0, true);
app.encoder.startBatch();

I need to wait untill media encoder (or internal encoder) has finished rendering and run external script.

I found some EncodeFinishedEvent in object model, but there's no any manual on how i can use it.