Function load_variants_for_contig 

pub fn load_variants_for_contig(
    path: &Path,
    contig_name: &str,
    sample_name: Option<&str>,
    _dict: &SequenceDictionary,
) -> Result<Vec<VariantRecord>>

Load variant records from a VCF for a given sample and contig.

Reads all records for contig_name, parses the GT field for the selected sample, and returns a sorted list of VariantRecords. Records where the sample’s genotype is homozygous reference or entirely missing are skipped.

Arguments

• path — Path to the VCF file.
• contig_name — Name of the contig to load variants for.
• sample_name — Sample name, or None to use the only sample in the VCF.
• _dict — Sequence dictionary (reserved for future validation).

Errors

Returns an error if the VCF cannot be read, the sample is not found, or GT fields are missing or malformed.