added experimental/composition. #168

Job	Run time
posix-cmake-install (ubuntu-22.04, OFF, 0)	1m 11s
posix-cmake-subdir (ubuntu-22.04, OFF, 0)	55s
posix-cmake-install (ubuntu-22.04, ON, 0)	43s
posix-cmake-test (ubuntu-22.04, OFF, 0)	3m 53s
posix (gcc-11, 2a, ubuntu-22.04)	3m 51s
posix-cmake-test (ubuntu-22.04, ON, 0)	3m 35s
posix-cmake-subdir (ubuntu-22.04, ON, 0)	34s
posix (gcc-12, 20,2b, ubuntu-22.04, g++-12)	7m 57s
posix-cmake-test (macos-13, OFF, 1)	6m 5s
posix-cmake-install (macos-13, OFF, 1)	1m 52s
posix-cmake-subdir (macos-13, OFF, 1)	1m 37s
posix (gcc-13, 20,2b, ubuntu-latest, ubuntu:23.04, g++-13)	8m 14s
posix-cmake-test (macos-13, ON, 1)	5m 15s
posix-cmake-install (macos-13, ON, 1)	1m 37s
posix-cmake-subdir (macos-13, ON, 1)	1m 39s
posix (clang, clang++-14, 20,2b, libc++, ubuntu-22.04, clang-14 libc++-14-dev)	7m 35s
posix (clang, 20,2b, macos-13, libc++, boost-container)	7m 36s
windows (msvc-14.3, 20,latest, 32,64, windows-2022)	19m 26s
windows-cmake-install (windows-2022, OFF)	3m 26s
windows (gcc, 2a, 64, windows-2019)	2m 17s
windows-cmake-install (windows-2022, ON)	2m 58s
windows-cmake-subdir (windows-2022, OFF)	2m 39s
windows-cmake-test (windows-2022, OFF)	8m 18s
windows-cmake-test (windows-2022, ON)	8m 33s
	1h 51m 46s

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