Add sample for Nexus cancellation #1073

Job	Run time
build-lint-test (3.10, ubuntu-latest)	11s
build-lint-test (3.14, macos-intel)	13s
build-lint-test (3.14, macos-arm)	26s
build-lint-test (3.10, windows-latest)	12s
build-lint-test (3.10, macos-intel)	12s
build-lint-test (3.14, windows-latest)	13s
build-lint-test (3.14, ubuntu-latest)	25s
build-lint-test (3.10, macos-arm)	12s
	2m 4s

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