Folly fbstring has the same trick, and it's a std::string compliant implementation used in production at Facebook. https://github.com/facebook/folly/blob/maste

Folly fbstring has the same trick, and it's a std::string compliant implementation used in production at Facebook. https://github.com/facebook/folly/blob/master/folly/docs/FBString.md#storage-strategies https://github.com/facebook/folly/blob/master/folly/docs/FBS...