Comment 13 for bug 1835968

With just this single patch reverted, the test case passes:

$ sudo patch -R -p2 < /home/ubuntu/0017-Reduce-memory-allocation-when-writing-to-SSLSocket.patch
patching file openssl/buffering.rb

ubuntu@ruby25-sru-1835968-bionic:~$ ./testcase-ruby-ssl.rb
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6.16.2Message sent via localhost; From ubuntu@localhost; To: ubuntu@localhost
6.37
You have new mail in /var/mail/ubuntu