Reduce OpenSSL::Buffering#do_write overhead #1298

Job	Run time
openssl-1.0.2u	50s
openssl-1.1.0l	59s
openssl-1.1.1w	1m 1s
ruby-versions / Generate Ruby versions	4s
openssl-3.0.15	1m 7s
openssl-3.1.7	56s
openssl-3.2.3	1m 2s
openssl-3.3.2	59s
openssl-3.4.0	1m 7s
openssl-master	3m 49s
libressl-3.1.5	54s
libressl-3.2.7	1m 6s
libressl-3.3.6	58s
libressl-3.4.3	58s
libressl-3.5.3	1m 5s
libressl-3.6.3	59s
libressl-3.7.3	55s
libressl-3.8.4	56s
libressl-3.9.2	1m 4s
libressl-4.0.0	1m 3s
openssl-3.0.15 with fips provider	59s
openssl-3.1.7 with fips provider	49s
openssl-3.2.3 with fips provider	56s
openssl-3.3.2 with fips provider	49s
openssl-3.4.0 with fips provider	49s
openssl-master with fips provider	3m 39s
openssl-3.4.0 without legacy provider	1m 4s
ubuntu-22.04 2.7	1m 0s
ubuntu-22.04 3.0	55s
ubuntu-22.04 3.1	1m 0s
ubuntu-22.04 3.2	1m 2s
ubuntu-22.04 3.3	1m 0s
ubuntu-22.04 3.4	1m 6s
ubuntu-22.04 head	57s
ubuntu-22.04 truffleruby	1m 32s
ubuntu-22.04 truffleruby-head	1m 45s
ubuntu-20.04 2.7	58s
ubuntu-20.04 3.0	55s
ubuntu-20.04 3.1	56s
ubuntu-20.04 3.2	58s
ubuntu-20.04 3.3	54s
ubuntu-20.04 3.4	58s
ubuntu-20.04 head	58s
ubuntu-20.04 truffleruby	1m 32s
ubuntu-20.04 truffleruby-head	1m 40s
macos-latest 2.7	53s
macos-latest 3.0	35s
macos-latest 3.1	37s
macos-latest 3.2	35s
macos-latest 3.3	36s
macos-latest 3.4	50s
macos-latest head	40s
macos-latest truffleruby	1m 13s
macos-latest truffleruby-head	1m 17s
windows-latest 2.7	5m 43s
windows-latest 3.0	3m 37s
windows-latest 3.1	5m 1s
windows-latest 3.2	5m 1s
windows-latest 3.3	4m 0s
windows-latest 3.4	16s
windows-latest head	5m 13s
windows-latest ucrt	3m 38s
windows-latest mswin	2m 36s
	1h 33m 24s

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