version of frontend switch.

enum of hub command codes.

enum of hub command codes.

enum of hub command codes.

enum of hub command codes.

outgoing request queue length.

base of numeric request id.

client Request contains original client request and a reply-to chan.

Hub exchanges messages between clients and plugs.

hub management command TODO: review if "string" is best carrier for replies.

The bundle of plugs with the same limit for the same vhost, The plugs in the bundle should be used equally, A simple round robin usage managed by a "next" index can be a starting point.

ProxyConn represents the websocket w/ a backend plug proxy.

a plug entry with a use count.

map of registered vhosts and plugs, Each host has multiple lists sorted by limits, each list can have multiple conns with same limit.

PlugResponse contains the plug response including the HTTP response and a chan to end of use.