That very in order guarantee is the issue. It can't know exactly where the connection died, which means that the client must inform the last time it received an update, and the server must then crawl back a log to find the pending messages and redispatch them.
At this point, long polling seems to carry more benefits, IMHO. WebSockets seem to be excellent for stable conditions, but not quite what we need for mobile.
> It can't know exactly where the connection died, which means that the client must inform the last time it received an update, and the server must then crawl back a log to find the pending messages and redispatch them.
I don't see how this is meaningfully different for long polling. The client could have received some updates but never ack'd it successfully over a long poll, so either way you need to keep a log and resync on reconnection.
At this point, long polling seems to carry more benefits, IMHO. WebSockets seem to be excellent for stable conditions, but not quite what we need for mobile.