Detecting end of file on 'file_source'?

I’m using the ‘file_source’ module to simulate a data stream. At the end
of a sequence of blocks,
I have a ‘message_sink’. However, I don’t seem to get any indication of
the end of file condition
when the file_source module detects that state.

Basically the message handler just hangs waiting for more messages.

Is there some ‘Except’ condition that is transmitted to python that I’m
missing.

Thanks
John C…