List<CachedOutputStreamCallback> callbacks = null;
if (os instanceof AbstractCachedOutputStream) {
callbacks = ((AbstractCachedOutputStream)os).getCallbacks();
}
c.send(message);
os = message.getContent(OutputStream.class);
if (os instanceof AbstractCachedOutputStream && callbacks.size() > 1) {
for (CachedOutputStreamCallback cb : callbacks) {
if (!(cb instanceof RetransmissionCallback)) {