Squashed 'circus_cs_plugin_sdk/' content from commit 3a02551

git-subtree-dir: circus_cs_plugin_sdk
git-subtree-split: 3a02551635d0091180ce0fe1cbb9b270447230e3
Merge commit '853e7916568c28cbe97139acb54f5a9779b88c53' as 'circus_cs_plugin_sdk'
Add subtree (circus_cs_plugin_sdk)