Just one more question if possible, wouldn't the adapter also take care of telling all other processes subscribed to the same adapter to emit a message (and thus to all clients connected to those processes?) Ala:
To citate: "enables you to send messages between different processes running socket.io all using this same adapter.". So yes, this is basically the whole functionality of that adapter. They will fetch messages from the central storage and send them to the target, if the target is connected to them. Or in case of groups ("rooms"), send it to all in that group connected to them.