gmail Indox(#new message) implementation

[chekel]

Hi, I used gwt 2.4 to implement something very similar to the gmail
Indox(#new messages) idea as part of my menu. So basically, when my
gwt app load, it won't know when will new email arrive, but when
there's one, it will update the new messages number. I tried to used
rpc with AsyncCallback, but the rest of my app is freeze and seems
waiting the the server returns message back for new Mail. I tried to
used Request builder as well, but still not success. I looked in gwt
comet, but I am not sure what to do exactly with the server code to
extends CometRequest.

It would be appreciated if someone can give me more detail about this
on both the gwt client and the server side to push/long polling the
message.