Add ParallelEnumerate and Enumerate #244

Job	Run time
pack	2m 10s
build (ubuntu-latest, Debug)	1m 18s
build (ubuntu-latest, Release)	58s
build (windows-latest, Debug)	2m 47s
test-parsers (ubuntu-latest, Debug)	4m 12s
build (windows-latest, Release)	2m 45s
test-parsers (ubuntu-latest, Release)	4m 0s
build (macos-latest, Debug)	1m 48s
test-parsers (windows-latest, Debug)	7m 6s
build (macos-latest, Release)	2m 9s
test-parsers (windows-latest, Release)	6m 38s
test-parsers (macos-latest, Debug)	8m 45s
test-parsers (macos-latest, Release)	4m 38s
create-release-push	0s
	49m 14s

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