The `returns_len` argument type of `wasmer_export_func_returns_params`
must be `uint32_t` to match the `wasmer_export_func_returns_arity` results,
so that casts are not required.
The `params_len` argument type of `wasmer_export_func_params_arity`
must be `uint32_t` to match the `wasmer_export_func_*_arity` results,
so that casts are not required.