private static ImmutableHashSet <T> MergeOrIntersect(ImmutableHashSet <T> value1, ImmutableHashSet <T> value2, bool merge)
{
if (value1.IsEmpty)
{
return(value2);
}
else if (value2.IsEmpty || ReferenceEquals(value1, value2))
{
return(value1);
}
// PERF: Avoid additional allocations by using the overload that takes a set argument
// instead of IEnumerable argument.
return(merge ? value1.AddRange(value2) : value1.IntersectSet(value2));
}
