Increase default session timeout longer than default manager heartbeat interval about sockjs

[iceboy233]

The 5 seconds timeout was taken from nodejs disconnect_delay:
b0d7d17#diff-c4ae142f5c8b2a63ea9689afef142593

They are different parameters. nodejs disconnect_delay means interval to close the transport after client initiates the disconnect but the server does not respond (but it's also used when initiating the connection):
https://github.com/sockjs/sockjs-node/blob/4c9f3009be13962b0785138ccdf527c5abe925f6/lib/session.js

nodejs has a different heartbeat_delay for heartbeat, and it's still different from the timeout:
https://github.com/sockjs/sockjs-node/blob/4c9f3009be13962b0785138ccdf527c5abe925f6/lib/transport/websocket.js#L78

This was working fine until the heartbeat behavior silently changed:
9c29e99#diff-c4ae142f5c8b2a63ea9689afef142593R306

[asvetlov]

Ooh. Very sorry for long delay.

Please make a PR.
I believe the timeout should be about 1 min.
Or heartbit should be decreased to 15 secs with 40 secs timeout.
@fafhrd91 ?

[fafhrd91]

i am fine

[asvetlov]

Would you make a PR with the fix?

[iceboy233]

What would be the best fix for this? Some options:

1. Simply make timeout longer than heartbeat.
2. Mimic nodejs client library.
3. Separate heartbeat and timeout, make heartbeat similar to nats ping/pong.

[maparent]

It seems to be worse than that; the call to Session._heartbeat does not seem to call Session._tick, which updates Session.expires. So the session expires at the end of timeout, irrespective of the relative value of timeout and heartbeat. We should make sure _tick is called; I would think right after the dequeue in Session._wait.

[jersobh]

Closing this issue since #265 is merged.