Add disclaimer to the env api. #1840

Job	Run time
downstream	5m 27s
clang-sanitizers (,thread)	2m 43s
clang-sanitizers (,address,undefined)	2m 11s
linux-compiler-compat (clang-3)	2m 14s
linux-compiler-compat (clang-6)	4m 16s
linux-compat (manylinux1-x64)	1m 27s
linux-shared-libs	2m 14s
linux-no-cpu-extensions	2m 13s
linux-compiler-compat (clang-8)	4m 54s
linux-compat (manylinux1-x86)	1m 47s
linux-compiler-compat (clang-9)	4m 24s
linux-compat (manylinux2014-x64)	1m 45s
windows	4m 42s
linux-compiler-compat (clang-10)	2m 9s
linux-compat (manylinux2014-x86)	2m 23s
linux-compiler-compat (clang-11)	2m 51s
linux-compat (raspbian-bullseye)	10m 27s
windows-shared-libs	4m 1s
linux-compiler-compat (gcc-4.8)	1m 38s
linux-compat (fedora-34-x64)	1m 39s
windows-vc14 (x86)	3m 15s
linux-compat (opensuse-leap)	2m 22s
linux-compiler-compat (gcc-5)	2m 6s
windows-vc14 (x64)	3m 17s
linux-compiler-compat (gcc-6)	2m 20s
linux-compat (rhel8-x64)	1m 32s
linux-compat (al2-x64)	1m 37s
linux-compiler-compat (gcc-7)	1m 46s
windows-vc15 (x86)	2m 52s
linux-compiler-compat (gcc-8)	2m 10s
windows-vc15 (x64)	3m 49s
linux-compiler-compat (gcc-11)	2m 11s
windows-vc16 (x86)	3m 34s
windows-vc16 (x64)	4m 6s
osx	2m 54s
osx-no-cpu-extensions	2m 57s
windows-app-verifier	16m 37s
windows-no-cpu-extensions	3m 50s
Cross Compile linux-armv6	2m 23s
linux-debug	1m 43s
openbsd	13m 19s
Cross Compile linux-armv7	2m 24s
Cross Compile linux-arm64	2m 11s
windows-debug	3m 52s
Cross Compile android-armv7	2m 52s
osx-debug	3m 0s
	2h 40m 24s

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