distance map now holds the edge the current path is coming from,
removing the need for next map.
Both distance map and distanceHeap now hold pointers instead of the full
struct to reduce allocations and copies.
Both these changes reduced path finding time by ~5% and memory usage by
~2mb.
Pre-sizing these structures avoids a lot of map resizing, which causes
copies and rehashing of entries. We mostly know that the map won't
exceed that size, and it doesn't affect memory usage in any significant
way.
Calling `ForEachNode` hits the DB, and allocates and parses every node
in the graph. Walking the channels also loads nodes from the DB, so this
meant that each node was read/parsed/allocated several times per run.
This reduces runtime by ~10ms and memory usage by ~4mb.
The server was kept alive long after it stopped being used. This caused
problems for services using long-lived GRPC connections which might be
created before wallet unlocked. They got stuck connected to the wallet
unlock service needing a restart.
Juan Pablo Civile