Added an extra step to the datagram negotation process. Before

the server starts sending datagrams willy-nilly, it must wait for 
a (reliable) go-ahead from the client.  Otherwise, it's possible 
that the server may be successfully receiving datagrams but not 
sending them.


git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@5792 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/presents/client/BlockingCommunicator.java

@@ -56,6 +56,7 @@ import com.threerings.presents.net.AuthResponseData;
 import com.threerings.presents.net.DownstreamMessage;
 import com.threerings.presents.net.LogoffRequest;
 import com.threerings.presents.net.PingRequest;
+import com.threerings.presents.net.TransmitDatagramsRequest;
 import com.threerings.presents.net.Transport;
 import com.threerings.presents.net.UpstreamMessage;
 import com.threerings.presents.util.DatagramSequencer;
@@ -766,6 +767,9 @@ public class BlockingCommunicator extends Communicator
             if (cport > 0) {
                 log.info("Datagram connection established", "port", cport);
 
+                // notify the server
+                postMessage(new TransmitDatagramsRequest());
+
                 // start up the writer thread
                 _datagramWriter = new DatagramWriter();
                 _datagramWriter.start();