feat: mman `NonNull` #31

Job	Run time
minver	13s
macos	1m 30s
rust_stable	50s
linux_native_builds (x86_64-unknown-linux-gnu)	1m 34s
rustfmt	8s
tier3 (x86_64-unknown-dragonfly)	1m 11s
linux_native_builds (x86_64-unknown-linux-musl)	1m 39s
tier3 (x86_64-unknown-openbsd)	54s
tier3 (armv7-unknown-linux-uclibceabihf)	1m 22s
tier3 (x86_64-unknown-haiku)	54s
redox	54s
cross (arm-unknown-linux-gnueabi)	1m 33s
cross (armv7-unknown-linux-gnueabihf)	2m 28s
cross_compiling (aarch64-linux-android)	28s
cross (i686-unknown-linux-gnu)	2m 8s
cross_compiling (arm-linux-androideabi)	2m 25s
cross (i686-unknown-linux-musl)	2m 43s
cross_compiling (armv7-linux-androideabi)	39s
cross (mips-unknown-linux-gnu)	2m 21s
cross_compiling (i686-linux-android)	41s
cross (mips64-unknown-linux-gnuabi64)	1m 38s
cross_compiling (x86_64-linux-android)	46s
cross (mips64el-unknown-linux-gnuabi64)	1m 29s
cross_compiling (arm-unknown-linux-musleabi)	42s
cross (mipsel-unknown-linux-gnu)	2m 9s
cross_compiling (x86_64-unknown-fuchsia)	25s
cross (powerpc64le-unknown-linux-gnu)	2m 31s
cross_compiling (x86_64-unknown-illumos)	35s
cross_compiling (aarch64-apple-ios, true)	34s
cross_compiling (powerpc64-unknown-linux-gnu)	49s
cross_compiling (s390x-unknown-linux-gnu)	54s
cross_compiling (x86_64-unknown-linux-gnux32)	43s
cross_compiling (x86_64-unknown-netbsd)	20s
	40m 10s

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