How to decode the output from pgoutput

Hi,

I'm writing a tool to process a logical replication stream. The intent is
to use publications and subscriptions as an initial filter, and then use
the replication stream to trigger external events. So my tool should
connect to the master in the same manner as a replication slave, but it
does different things with the data.

So far I've used pg_recvlogical.c as a guide and I'm successfully
connecting to the master, creating a replication slot, and subscribing to a
couple of publications.

But now I'm stuck at further interpreting the data. Can anybody point me
to further documentation or the right code to look at to figure out the
format of the WAL data stream?

Cheers,
Ami.