+ * The internal representation of a `std::string` is private.
+ * We could add some code to read this for a given implementation.
+ * However, even if we focus on GNU libstdc++ with Itanium ABI
+ * GNU libstdc++ currently has two different ABIs
+ *
+ * * the pre-C++11 is a pointer to a ref-counted
+ * string-representation (with support for COW);
+ *
+ * * the [C++11-conforming implementation](https://gcc.gnu.org/gcc-5/changes.html)
+ * does not use refcouting/COW but has a small string optimization.