Is fuzztest supposed to be usable with non-googletest frameworks?

The readme states:

> You can use it together with [GoogleTest](https://google.github.io/googletest/), or other unit testing frameworks

However, the public APIs seem to require that you use gtest to run tests since that seems to be the only supported way to launch the tests. All of the required APIs to do anything else are in internal headers and/or namespaces. At the very least, I think the `Runtime`, `ForEachTest`, `FuzzTest`, and `Configuration` would need to be made public. Or at least have some sanitized public wrapper.

There are also some cases in the current codebase where it is fuzzy (pardon the pun) whether they are intended to be public or internal. For example the methods on `Registration` are documented as part of the public API, but they are in an internal header and namespace. `GetRegistration` and `RegisterFuzzTest` are both in internal headers but seem to be explicitly outside of the internal namespace. Are they intended to be public or internal?