replace legacy impl with Poll #761

Job	Run time
test (armv7-unknown-linux-gnueabihf, nightly)	1m 14s
test (x86_64-unknown-linux-gnu, nightly)	11m 26s
test (aarch64-unknown-linux-gnu, nightly)	1m 15s
test (aarch64-unknown-linux-gnu, stable)	1m 13s
test (armv7-unknown-linux-gnueabihf, stable)	1m 11s
test (x86_64-unknown-linux-gnu, stable)	6m 13s
test (riscv64gc-unknown-linux-gnu, nightly)	1m 8s
test (riscv64gc-unknown-linux-gnu, stable)	1m 24s
test (s390x-unknown-linux-gnu, nightly)	1m 15s
test (loongarch64-unknown-linux-gnu, nightly)	1m 15s
test (aarch64-apple-darwin, nightly)	4m 52s
test (s390x-unknown-linux-gnu, stable)	1m 13s
test (x86_64-apple-darwin, nightly)	5m 15s
test (loongarch64-unknown-linux-gnu, stable)	1m 25s
test (i686-pc-windows-gnu, stable)	6m 29s
test (aarch64-apple-darwin, stable)	4m 19s
test (i686-pc-windows-msvc, stable)	4m 7s
test (x86_64-pc-windows-gnu, nightly)	6m 37s
test (i686-pc-windows-msvc, nightly)	4m 43s
test (x86_64-pc-windows-msvc, stable)	7m 2s
test (i686-pc-windows-gnu, nightly)	10m 41s
test (x86_64-apple-darwin, stable)	2m 38s
test (x86_64-pc-windows-msvc, nightly)	7m 30s
test (x86_64-pc-windows-gnu, stable)	3m 28s
	1h 37m 53s

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