Resend any reliable messages received before startup

We want to be able to publish (and receive) low frequency configuration
messages.  This lets us make those *not* periodic when we move them
across nodes, simplifying the system.

This takes some special tracking at startup.  We very much don't want to
re-send messages already sent.  That would result in 2 receive
timestamps for a single node for 1 send packet, probably breaking log
sorting.  I'm not interested in learning what would break...

Change-Id: I489460cd4919907516e504e6694d7cef544b0da6
diff --git a/aos/network/sctp_server.h b/aos/network/sctp_server.h
index 8fa3d15..e18517a 100644
--- a/aos/network/sctp_server.h
+++ b/aos/network/sctp_server.h
@@ -36,6 +36,9 @@
   bool Send(std::string_view data, sctp_assoc_t snd_assoc_id, int stream,
             int timetolive);
 
+  // Aborts a connection.  Returns true on success.
+  bool Abort(sctp_assoc_t snd_assoc_id);
+
   int fd() { return fd_; }
 
   // Enables the priority scheduler.  This is a SCTP feature which lets us