Index and write word16 array #9

Job	Run time
build (ubuntu-latest, 8.6, 3.8.1.0)	9m 40s
i386	9m 32s
build (ubuntu-latest, 8.8, 3.8.1.0)	27m 48s
darwin_arm (self-hosted, macOS, ARM64, 8.10.7)	58s
arm (arm32v7)	10m 10s
build (ubuntu-latest, 8.10, 3.8.1.0)	10m 19s
darwin_arm (self-hosted, macOS, ARM64, 9.2.8)	58s
arm (arm64v8)	32m 5s
build (ubuntu-latest, 9.0, 3.8.1.0)	9m 49s
darwin_arm (self-hosted, macOS, ARM64, 9.4.7)	52s
build (ubuntu-latest, 9.2, 3.8.1.0)	8m 55s
build (ubuntu-latest, 9.4, 3.8.1.0)	10m 39s
build (ubuntu-latest, 9.6, 3.8.1.0)	9m 23s
build (ubuntu-latest, 9.8, 3.8.1.0)	8m 22s
build (macOS-latest, 9.4, 3.8.1.0)	26m 6s
build (macOS-latest, 9.6, 3.8.1.0)	29m 58s
build (windows-latest, 9.4, 3.8.1.0)	44m 28s
build (windows-latest, 9.6, 3.8.1.0)	48m 54s
	4h 58m 56s

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