Turn on exclusive senders in LogReader

This makes it so that we now automatically detect situations where a
user attempts to send messages during replay that are simultaneously
*being* replayed.

Change-Id: I40f30693fe93c94018b6ddbc9f748e655cdf1fe3
Signed-off-by: James Kuszmaul <james.kuszmaul@bluerivertech.com>
diff --git a/aos/network/timestamp_channel.h b/aos/network/timestamp_channel.h
index e35a170..d95edda 100644
--- a/aos/network/timestamp_channel.h
+++ b/aos/network/timestamp_channel.h
@@ -59,6 +59,8 @@
 
   aos::Sender<RemoteMessage> *SenderForChannel(const Channel *channel,
                                                const Connection *connection);
+  void ClearSenderForChannel(const Channel *channel,
+                             const Connection *connection);
 
  private:
   aos::EventLoop *event_loop_;