For my benchmarks on aggregation this reduces allocations by ~5% (~10%
time improvement):
```
benchmark old ns/op new ns/op delta
BenchmarkEvaluations/benchdata/aggregators.test/promxy-4 727692 649626 -10.73%
benchmark old allocs new allocs delta
BenchmarkEvaluations/benchdata/aggregators.test/promxy-4 2566 2434 -5.14%
benchmark old bytes new bytes delta
BenchmarkEvaluations/benchdata/aggregators.test/promxy-4 162760 148854 -8.54%
```
Signed-off-by: Thomas Jackson <jacksontj.89@gmail.com>
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