Remove usage of IO internals. #711

Job	Run time
openssl-1.0.2u	2m 59s
openssl-1.1.0l	2m 49s
openssl-1.1.1t	2m 23s
openssl-3.0.8	5m 30s
libressl-3.1.5	2m 55s
libressl-3.2.7	3m 22s
libressl-3.3.6	2m 58s
libressl-3.4.3	3m 6s
libressl-3.5.3	3m 9s
libressl-3.6.1	3m 4s
libressl-3.7.0	3m 30s
openssl-3.0.8 fips	4m 42s
ruby-versions / Generate Ruby versions	2s
ubuntu-22.04 2.6	1m 30s
ubuntu-22.04 2.7	1m 11s
ubuntu-22.04 3.0	1m 17s
ubuntu-22.04 3.1	1m 17s
ubuntu-22.04 3.2	1m 8s
ubuntu-22.04 head	1m 16s
ubuntu-22.04 truffleruby	51s
ubuntu-22.04 truffleruby-head	1m 5s
ubuntu-20.04 2.6	1m 24s
ubuntu-20.04 2.7	1m 7s
ubuntu-20.04 3.0	1m 14s
ubuntu-20.04 3.1	1m 22s
ubuntu-20.04 3.2	1m 6s
ubuntu-20.04 head	1m 15s
ubuntu-20.04 truffleruby-head	58s
macos-latest 2.6	2m 3s
macos-latest 2.7	2m 4s
macos-latest 3.0	1m 22s
macos-latest 3.1	2m 56s
macos-latest 3.2	1m 44s
macos-latest head	1m 21s
macos-latest truffleruby-head	3m 29s
windows-latest 2.6	7m 30s
windows-latest 2.7	6m 18s
windows-latest 3.0	6m 25s
windows-latest 3.1	6m 45s
windows-latest 3.2	8m 29s
windows-latest ucrt	5m 42s
windows-latest mswin	3m 36s
	1h 58m 14s

Provide feedback