Function gfautil::variants::detect_variants_against_ref_

pub fn detect_variants_against_ref_(
    segment_sequences: &FnvHashMap<usize, BString>, 
    ref_name: &[u8], 
    ref_path: &[(usize, usize, Orientation)], 
    query_path: &[(usize, usize, Orientation)]
) -> FnvHashMap<VariantKey, FnvHashSet<Variant>>

NB Should be equivalent to detect_variants_against_ref in function, but I need to test it, and I'm not sure about how performance may differ