asynchronous data from server

I am in the design stage of a project (actually designing new
functionality for an existing project)

This project currently is using the Indy 9 TIdTCPClient and
TIdTCPServer classes.  Looking at the docs, I do not see how I
can push data from the server.  (I could poll from the client but
would prefer not to.)

I am used to the generic Delphi sockets where you can send data
from either end.  If you can do this with the indy sockets,
please point me to an example.

Thanks.