Remove usage of unstable features (#332) (#331) #90

Job	Run time
macOS	48s
Windows (x86_64-pc-windows-msvc)	50s
macOS (force-inprocess)	52s
Windows (i686-pc-windows-msvc)	59s
Linux	31s
macOS (async)	1m 33s
Windows (--features force-inprocess, x86_64-pc-windows-msvc)	53s
Linux (force-inprocess)	34s
Windows (--features force-inprocess, i686-pc-windows-msvc)	52s
Linux (memfd)	29s
Windows (--features windows-shared-memory-equality, x86_64-pc-windows-msvc)	1m 18s
Linux (async)	37s
Windows (--features windows-shared-memory-equality, i686-pc-windows-msvc)	1m 4s
Windows (--features async, x86_64-pc-windows-msvc)	1m 3s
Windows (--features async, i686-pc-windows-msvc)	1m 7s
Result	2s
	13m 32s

Provide feedback