These variables are being initialized via calls to `enif_get_uint`,
so it's safer to declare them as unsigned int's rather than size_t's.
Their being used in calls to `enif_alloc_binary`, which takes a size_t
as its size.
However, the resulting ErlNifBinary keeps its size as an unsigned int,
so asking for a size that's an unsigned int should be safe.
This would be problematic in the case where sizeof(size_t) <
sizeof(unsigned), which would mean we're getting fewer bytes allocated
than expected.
Perhaps an explicit check for, for example, `hashSize > MAX_SIZE` would
be good here?