wait readable/writable
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53642 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
wait readable/writable
wait for multiple modes, readable and writable, at once. the
arguments may change in the future. [Feature #12013]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53642 b2dd03c8-39d4-4d8f-98ff-823fe69b080e