This fixes a flake I've seen in the wild lately:
```
--- FAIL: TestBlockDifferenceFix (0.01s)
router_test.go:4335: height should have been updated to 5, instead got 4
FAIL
FAIL github.com/lightningnetwork/lnd/routing 3.865s
FAIL
```
We wrap things in an assertion loop to ensure that timing quirks don't
cause the test to fail sporadically.
The routing package implements authentication+validation of channel
announcements, pruning of the channel graph, path finding within the network,
sending outgoing payments into the network and synchronizing new peers to our
channel graph state.
Installation and Updating
⛰ go get -u github.com/lightningnetwork/lnd/routing