Function IORegistryIteratorEnterEntry 

pub unsafe extern "C-unwind" fn IORegistryIteratorEnterEntry(
    iterator: io_iterator_t,
) -> kern_return_t

Available on crate feature libc only.

Recurse into the current entry in the registry iteration.

This method makes the current entry, ie. the last entry returned by IOIteratorNext, the root in a new level of recursion.

Returns: A kern_return_t error code.