* @return a non-null set of VCFHeaderLines
*/
public Set<VCFHeaderLine> getVCFHeaderLines() {
final Set<VCFHeaderLine> headerLines = new LinkedHashSet<>();
// TODO - do we need a new kind of VCF Header subclass for specifying arbitrary alternate alleles?
headerLines.add(new VCFSimpleHeaderLine(ALTERNATE_ALLELE_STRING, GATKVariantContextUtils.NON_REF_SYMBOLIC_ALLELE_NAME, "Represents any possible alternative allele at this location"));
//headerLines.add(new VCFFormatHeaderLine(INDEL_INFORMATIVE_DEPTH, 1, VCFHeaderLineType.Integer, "Number of reads at locus that are informative about an indel of size <= " + indelInformativeDepthIndelSize));
return headerLines;
}