Prevent heap allocations in FiveTuple Fingerprint

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 68.42105% with 6 lines in your changes are missing coverage. Please review.

Project coverage is 27.87%. Comparing base (cf40c33) to head (a9f47d0).

Files	Patch %	Lines
internal/allocation/five_tuple.go	72.22%	5 Missing :warning:
internal/allocation/allocation_manager.go	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #390 +/- ## =========================================== - Coverage 68.24% 27.87% -40.38% =========================================== Files 43 43 Lines 2337 2353 +16 =========================================== - Hits 1595 656 -939 - Misses 576 1652 +1076 + Partials 166 45 -121 ``` | [Flag](https://app.codecov.io/gh/pion/turn/pull/390/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pion) | Coverage Δ | | |---|---|---| | [go](https://app.codecov.io/gh/pion/turn/pull/390/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pion) | `?` | | | [wasm](https://app.codecov.io/gh/pion/turn/pull/390/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pion) | `27.87% <68.42%> (+0.27%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pion#carryforward-flags-in-the-pull-request-comment) to find out more.

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