Index: src/java/org/apache/avro/ipc/Responder.java
===================================================================
--- src/java/org/apache/avro/ipc/Responder.java	(revision 789903)
+++ src/java/org/apache/avro/ipc/Responder.java	(working copy)
@@ -69,6 +69,13 @@
         return bbo.getBufferList();
 
       // read request using remote protocol specification
+      //   incoming per-call metadata from the Requestor
+      for (long i = in.readMapStart(); i != 0; i = in.mapNext()) {
+        for (long j = 0; j < i; j++) {
+          in.readString(null);    // consume and discard key
+          in.readBytes(null); // consume and discard value
+        }
+      }
       String messageName = in.readString(null).toString();
       Message m = remote.getMessages().get(messageName);
       if (m == null)
@@ -90,6 +97,8 @@
         error = new AvroRemoteException(new Utf8(e.toString()));
       }
 
+      out.writeMapStart();    // Write out per-call metadata as a map
+      out.writeMapEnd();      //   (for now, an empty map)
       out.writeBoolean(error != null);
       if (error == null)
         writeResponse(m.getResponse(), response, out);
Index: src/java/org/apache/avro/ipc/Requestor.java
===================================================================
--- src/java/org/apache/avro/ipc/Requestor.java	(revision 789903)
+++ src/java/org/apache/avro/ipc/Requestor.java	(working copy)
@@ -75,6 +75,8 @@
       if (m == null)
         throw new AvroRuntimeException("Not a local message: "+messageName);
       
+      out.writeMapStart();                // Write out per-call metadata as a map
+      out.writeMapEnd();                  //   (for now, an empty map)
       out.writeString(m.getName());       // write message name
       writeRequest(m.getRequest(), request, out); // write request payload
       
@@ -91,6 +93,15 @@
     m = getRemote().getMessages().get(messageName);
     if (m == null)
       throw new AvroRuntimeException("Not a remote message: "+messageName);
+    
+    //  per-call metadata returned from the Responder
+    for (long i = in.readMapStart(); i != 0; i = in.mapNext()) {
+      for (long j = 0; j < i; j++) {
+        in.readString(null);    // consume and discard key
+        in.readBytes(null); // consume and discard value
+      }
+    }
+    
     if (!in.readBoolean()) {                      // no error
       return readResponse(m.getResponse(), in);
     } else {