Sending out messages on block shutdown

[Martin Luelf]

Dear list,

I have a custom frame sync block that takes a stream of complex samples 
as inputs (output signature is 0,0) and outputs PDU messages if frames 
were found. When the upstream block is done I would still like to send 
out a few messages (flushing an internal buffer), before shutting down 
the block and signaling the subscribed block that we are done.

With GNURadio 3.7 I sent out these messages in the stop() method 
followed by an PMT EOF object, which worked great.

Now I finally ported my block to 3.8 and noticed that the messages send 
out during the stop() call are no longer received by the subscribed block.

Is there a way to find out that the call to the work function is going 
to be the last call, or is there another way of learning that the block 
is being stopped at a time where the subscribed block is still listening 
for messages?

Yours
Martin