Writing native extensions for the standalone Dart VM isn't that hard. It requires some previous knowledge of C/C++ and ideally compilers as well, but the approach is very straightforward and the potential is limited only by your imagination.

Native extensions for Dart are quite specific and you're definitely not going to use them every day, but it's good to know that you can reuse a lot of existing libraries written in C/C++ and achieve very good performance when you need it.