Squashed 'helpers/' changes from a4b29df2c..d478a5faa
Squashed 'helpers/' changes from a4b29df2c..d478a5faa

d478a5faa Improve staleness check for ReadCache.
7520a76a1 Merge pull request #298 in VFS/helpers from feature/VFS-4284-add-helpers-native-performance-tests to develop

git-subtree-dir: helpers
git-subtree-split: d478a5faa5154d77a89f0adbfb8d0273897dee60

onedata/oneclient,onedata/oneclient,onedata/oneclient,onedata/oneclient