[HACKERS] remote_apply for logical replication?

Hi,

In src/backend/replication/logical/worker.c:
   pq_sendbyte(reply_message, 'r');   pq_sendint64(reply_message, recvpos);       /* write */
pq_sendint64(reply_message,flushpos);      /* flush */   pq_sendint64(reply_message, writepos);      /* apply */
 

Is 'writepos' really applied?  Why do we report the merely received
position as written?

I haven't tried any of this stuff out yet so this may be a stupid
question, but I'm wondering: should xinfo &
XACT_COMPLETION_APPLY_FEEDBACK trigger logical replication to send a
reply, so that synchronous_commit = remote_apply would work?

-- 
Thomas Munro
http://www.enterprisedb.com