Chapter overview:
  * How path finding works in the network

Relevant questions to answer:
  * What is packet switching? What is circuit switching? Which one does LN use today?
  * In the abstract what is path finding?
  * What is dijkstra's? What modifications need to be made to apply it to this domain?
  * Why must path finding happen backwards (receiver to sender)?
  * How is the information contained in a channel update used in path finding?
  * How can errors sent during payment routing help the sender to narrow their search space?
  * What is payment splitting? How does it work?
  * What information can be sent to intermediate and the final node aside from the critical routing data?
  * What are multi-hop locks? What addition privacy and security guarantees to they offer?
  * How can the flexible onion space be used to enabled packet switching in the network?