Hotspots in the benchmark.

[planetis-m]

From the benchmark's results for our custom mutator from left to right, about:

1. 15% of the time is spent in deserializing the input.
2. 11% serializing the mutated input.
3. 36% running myMutator
4. 20% initRand

Aggregated costs of running important procs:

1. 1.4% byteSize
2. 3% sample
3. 1% running eqeq (that's seq's ==)
4. 9% copying the selected item before mutation.
5. 10% rand()
6. 20% mutateSeq
7. postProcess doesn't appear anywhere.

Reproduce: Benchmark runs with -d:fuzzerStandalone and --mm:arc

[planetis-m]

Note: According to LibFuzzer's interface: "Should produce the same mutation given the same seed." This applies to minimizing where the crash input is given a different seed each mutation. So I don't know if optimizing rand out is possible.