For most strings, it seems to be that using a varint would solve the overhead problem. For short strings the overhead would be no longer than the null byte (which you could discard, except when interacting with existing APIs).

But as with _all_ string solutions, it's the POSIX interface, standard library, and other libraries that screw you. If you're programming in C today, it's because you're integrating with a ton of C code, and thus it's impossible to make progress since the scope of improvement is so small.

It's always struck me as weird that Rust treats strings the way it does - the capacity value is not useful for many cases of strings, and it would have cost them one bit to special case the handling constant strings without the cap measure, which would be better. Most strings are _short_ which makes the overhead worse, proportionally.