Reduce OpenSSL::Buffering#do_write overhead #1305

Job	Run time
openssl-1.0.2u	57s
openssl-1.1.0l	55s
openssl-1.1.1w	55s
openssl-3.0.15	58s
openssl-3.1.7	1m 4s
openssl-3.2.3	56s
openssl-3.3.2	1m 1s
openssl-3.4.0	1m 3s
openssl-master	3m 52s
libressl-3.1.5	55s
libressl-3.2.7	58s
libressl-3.3.6	1m 3s
libressl-3.4.3	59s
libressl-3.5.3	1m 0s
libressl-3.6.3	54s
libressl-3.7.3	59s
libressl-3.8.4	57s
libressl-3.9.2	1m 2s
libressl-4.0.0	54s
openssl-3.0.15 with fips provider	51s
openssl-3.1.7 with fips provider	51s
openssl-3.2.3 with fips provider	55s
openssl-3.3.2 with fips provider	51s
openssl-3.4.0 with fips provider	57s
openssl-master with fips provider	3m 39s
openssl-3.4.0 without legacy provider	1m 2s
ruby-versions / Generate Ruby versions	3s
ubuntu-22.04 2.7	1m 5s
ubuntu-22.04 3.0	54s
ubuntu-22.04 3.1	59s
ubuntu-22.04 3.2	1m 1s
ubuntu-22.04 3.3	1m 3s
ubuntu-22.04 3.4	1m 8s
ubuntu-22.04 head	58s
ubuntu-22.04 truffleruby	1m 37s
ubuntu-22.04 truffleruby-head	1m 47s
ubuntu-20.04 2.7	1m 2s
ubuntu-20.04 3.0	53s
ubuntu-20.04 3.1	1m 4s
ubuntu-20.04 3.2	1m 1s
ubuntu-20.04 3.3	55s
ubuntu-20.04 3.4	58s
ubuntu-20.04 head	56s
ubuntu-20.04 truffleruby	1m 29s
ubuntu-20.04 truffleruby-head	1m 43s
macos-latest 2.7	1m 1s
macos-latest 3.0	50s
macos-latest 3.1	38s
macos-latest 3.2	40s
macos-latest 3.3	42s
macos-latest 3.4	50s
macos-latest head	38s
macos-latest truffleruby	57s
macos-latest truffleruby-head	59s
windows-latest 2.7	5m 29s
windows-latest 3.0	3m 53s
windows-latest 3.1	4m 11s
windows-latest 3.2	4m 52s
windows-latest 3.3	4m 9s
windows-latest 3.4	4m 1s
windows-latest head	4m 27s
windows-latest ucrt	3m 56s
windows-latest mswin	3m 6s
	1h 36m 23s

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