Re: pg_recvlogical: Prevent flushed data from being re-sent after restarting replication

Hi, 

Thanks for the patch updates.  

Maybe it's better to use slurp_file(). We already have wait_for_log() to
wait for a message in the cluster's log file, but there's no helper function
to wait for specific content to appear in an arbitrary file.

To support waiting for output in pg_recvlogical's output file,
I added a new helper that uses slurp_file() (see the attached 0002 patch).
I also updated the 0003 patch (the pg_recvlogical reconnection test) to
use this helper instead of pg_read_file(). Thoughts?

Agreed, nice addition. 

I applied the v3-000* patch set and it builds successfully and passes the tests on my laptop. 

However the CI seems not completely happy yet, with previous 2 runs not green for Windows. Could it be there's an issue with executing the test on Windows? 

-- 
Thanks,
Mircea Cadariu