Remove dependency on waker-fn #674

Job	Run time
fmt	10s
msrv (ubuntu-latest, 1.63)	1m 43s
clippy	31s
cross (ubuntu-latest)	1m 47s
msrv (windows-latest, 1.63)	1m 35s
security_audit	9s
test (ubuntu-latest, nightly)	1m 24s
windows_gnu (nightly, x86_64-pc-windows-gnu)	1m 45s
cross (macos-latest)	28s
test (ubuntu-latest, beta)	42s
test (ubuntu-latest, stable)	1m 12s
test (windows-latest, nightly)	2m 2s
test (windows-latest, beta)	1m 50s
test (windows-latest, stable)	2m 44s
test (macos-latest, nightly)	1m 47s
test (macos-latest, beta)	57s
test (macos-latest, stable)	52s
	21m 38s

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