The new onion uses the `channel_id` instead of the `node_id` of the
next hop to identify where to forward the payment. So we return the
exact channel chosen by the routing algo, to avoid having to look it
up again later.
We need some way to reflect the tradeoff between the possible delay if
a payment gets stuck, and the fees charged by nodes. This adds a risk
factor which reflects the probability that a node goes down, and the
cost associated with losing access to our funds for a given time.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This is less convenient to use, but makes far more sense for a real
user (like a wallet). It can ask about the route, then decide whether
to use it or not.
This will make even more sense once we add a parameter to control how
long we let the HTLC be delayed for, so a client can query for high,
medium and low tolerances and compare results.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>