This commits extends the mapper with functions for creating "delta"
MapResponses for different purposes (peer changed, peer removed, derp).
This wires up the new state management with a new StateUpdate struct
letting the poll worker know what kind of update to send to the
connected nodes.
Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>
This commit replaces the timestamp based state system with a new
one that has update channels directly to the connected nodes. It
will send an update to all listening clients via the polling
mechanism.
It introduces a new package notifier, which has a concurrency safe
manager for all our channels to the connected nodes.
Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>
