cancel_after is supported. #142

Job	Run time
posix-cmake-test (ubuntu-22.04, OFF, 0)	3m 27s
posix-cmake-install (ubuntu-22.04, OFF, 0)	40s
posix-cmake-test (ubuntu-22.04, ON, 0)	3m 32s
posix (gcc-11, 2a, ubuntu-22.04)	3m 49s
posix-cmake-install (ubuntu-22.04, ON, 0)	45s
posix-cmake-subdir (ubuntu-22.04, OFF, 0)	46s
posix (gcc-12, 20,2b, ubuntu-22.04, g++-12)	7m 48s
posix-cmake-test (macos-13, OFF, 1)	5m 10s
posix-cmake-install (macos-13, OFF, 1)	1m 29s
posix-cmake-subdir (ubuntu-22.04, ON, 0)	44s
posix (gcc-13, 20,2b, ubuntu-latest, ubuntu:23.04, g++-13)	8m 4s
posix-cmake-test (macos-13, ON, 1)	5m 37s
posix-cmake-install (macos-13, ON, 1)	1m 48s
posix-cmake-subdir (macos-13, OFF, 1)	1m 20s
posix (clang, clang++-14, 20,2b, libc++, ubuntu-22.04, clang-14 libc++-14-dev)	7m 22s
windows-cmake-install (windows-2022, OFF)	3m 6s
posix-cmake-subdir (macos-13, ON, 1)	1m 12s
posix (clang, 20,2b, macos-13, libc++, boost-container)	7m 1s
windows (msvc-14.3, 20,latest, 32,64, windows-2022)	17m 0s
windows-cmake-install (windows-2022, ON)	3m 9s
windows (gcc, 2a, 64, windows-2019)	1m 42s
windows-cmake-subdir (windows-2022, OFF)	3m 2s
windows-cmake-test (windows-2022, OFF)	7m 53s
windows-cmake-test (windows-2022, ON)	8m 3s
	1h 44m 29s

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