perf: only call removeHeader when needed

[gurgunday]

95% of the time, the header will not be defined when cookies are set, so there is no need to call removeHeader unless needed

Also, the setCookies function itself now resets the Map, which makes it easier to reason about what's going on

Median of 5 tests for 5 cookies

Old:

100 connections


┌─────────┬──────┬──────┬───────┬──────┬─────────┬─────────┬────────┐
│ Stat    │ 2.5% │ 50%  │ 97.5% │ 99%  │ Avg     │ Stdev   │ Max    │
├─────────┼──────┼──────┼───────┼──────┼─────────┼─────────┼────────┤
│ Latency │ 1 ms │ 1 ms │ 2 ms  │ 3 ms │ 1.06 ms │ 0.72 ms │ 120 ms │
└─────────┴──────┴──────┴───────┴──────┴─────────┴─────────┴────────┘
┌───────────┬───────┬───────┬─────────┬───────┬──────────┬────────┬───────┐
│ Stat      │ 1%    │ 2.5%  │ 50%     │ 97.5% │ Avg      │ Stdev  │ Min   │
├───────────┼───────┼───────┼─────────┼───────┼──────────┼────────┼───────┤
│ Req/Sec   │ 60159 │ 60159 │ 65791   │ 66367 │ 64938.19 │ 1708.4 │ 60153 │
├───────────┼───────┼───────┼─────────┼───────┼──────────┼────────┼───────┤
│ Bytes/Sec │ 19 MB │ 19 MB │ 20.8 MB │ 21 MB │ 20.5 MB  │ 539 kB │ 19 MB │
└───────────┴───────┴───────┴─────────┴───────┴──────────┴────────┴───────┘

Req/Bytes counts sampled once per second.
# of samples: 11

714k requests in 11.01s, 226 MB read

New:

100 connections


┌─────────┬──────┬──────┬───────┬──────┬─────────┬─────────┬────────┐
│ Stat    │ 2.5% │ 50%  │ 97.5% │ 99%  │ Avg     │ Stdev   │ Max    │
├─────────┼──────┼──────┼───────┼──────┼─────────┼─────────┼────────┤
│ Latency │ 1 ms │ 1 ms │ 2 ms  │ 2 ms │ 1.05 ms │ 0.66 ms │ 105 ms │
└─────────┴──────┴──────┴───────┴──────┴─────────┴─────────┴────────┘
┌───────────┬─────────┬─────────┬─────────┬─────────┬─────────┬────────┬─────────┐
│ Stat      │ 1%      │ 2.5%    │ 50%     │ 97.5%   │ Avg     │ Stdev  │ Min     │
├───────────┼─────────┼─────────┼─────────┼─────────┼─────────┼────────┼─────────┤
│ Req/Sec   │ 64575   │ 64575   │ 70783   │ 71359   │ 70160   │ 1838.4 │ 64549   │
├───────────┼─────────┼─────────┼─────────┼─────────┼─────────┼────────┼─────────┤
│ Bytes/Sec │ 20.4 MB │ 20.4 MB │ 22.4 MB │ 22.6 MB │ 22.2 MB │ 585 kB │ 20.4 MB │
└───────────┴─────────┴─────────┴─────────┴─────────┴─────────┴────────┴─────────┘

Req/Bytes counts sampled once per second.
# of samples: 11

772k requests in 11.01s, 244 MB read

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[gurgunday]

@mcollina can you please make a patch release after this is merged?

54e9bdc fixes a case where you set more than 1 cookie after the hook runs