# N=50000 warmup=1000
[seq]
  insert 50000: 0.04855 s, 971 ns/op
  n = 50000
  hit    50000: 0.064431 s, 1288 ns/op
  miss   50000: 0.02373201 s, 474 ns/op

[churn]
  20 cycles x 2500 entries = 50000 inserts + 20 gcs
  total 0.19157499 s, 3831 ns/op (insert+gc-sweep amortised)
  post-churn n = 7500

[held]
  n = 50000
  rand-hit 50000: 0.04980603 s, 996 ns/op
  seq-hit  50000: 0.06220302 s, 1244 ns/op

[hot single key]
  same-key 50000: 0.00110197 s, 22 ns/op

