Apparently, a component of Rails implements a buffering .write
method which keeps the String buffer around and makes it unsafe
for us to clear it after calling .write.
This caused Rack::Deflater to give empty results when enabled.
Fortunately, per r61631 / a55abcc0ca,
this misguided optimization was only worth a small (0.5MB) savings
and we still benefit from the majority of the memory savings in
that change.
Thanks to zunda for the bug report.
[ruby-core:90133] [Bug #15356]
Fixes: r61631 (commit a55abcc0ca)
("zlib: reduce garbage on gzip writes (deflate)")
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66268 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
cc9b57a2b4