There's now a critical slowdown in creating the
shortest paths. The queue is growing monotonically. Why?
```bash
^C[rule146@rule146: nth-bacon]$ node nthbacon.js
Building costar graph ...
Constructing shortest paths to Kevin Bacon ...
1000 keys marked
queue length = 995
2000 keys marked
queue length = 1972
3000 keys marked
queue length = 2956
4000 keys marked
queue length = 3944
5000 keys marked
queue length = 4883
6000 keys marked
queue length = 5848
7000 keys marked
queue length = 6823
8000 keys marked
queue length = 7775
9000 keys marked
queue length = 8730
10000 keys marked
queue length = 9691
11000 keys marked
queue length = 10636
12000 keys marked
queue length = 11599
13000 keys marked
queue length = 12527
```