Is rpmalloc_initialize not called?

[tomaka]

The README of rpmalloc mentions:

Before calling any other function in the API, you MUST call the initialization function, either rpmalloc_initialize or rpmalloc_initialize_config, or you will get undefined behaviour when calling other rpmalloc entry point.

When I saw this note I was curious about how this was done in Rust and I looked at the source code of this crate, but I can't find anywhere where rpmalloc_initialize or rpmalloc_initialize_config is being called?
If this is called somewhere and I just didn't see it, then sorry for the noise.