Update hashbrown dependency and API adjustments #52

Job	Run time
build (stable, ubuntu-latest)	49s
build (stable, windows-latest)	2m 25s
build (stable, macOS-latest)	27s
build (nightly, ubuntu-latest)	32s
build (nightly, windows-latest)	1m 29s
build (nightly, macOS-latest)	32s
	6m 14s

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