in Sources/OrderedCollections/HashTable/_HashTable+UnsafeHandle.swift [213:221]
func _bucketContents(for value: Int?) -> UInt64 {
guard var value = value else { return 0 }
let mask = Int(truncatingIfNeeded: bucketMask)
assert(value >= 0 && value < mask)
value &-= bias
if value < 0 { value += mask }
assert(value >= 0 && value < mask)
return UInt64(truncatingIfNeeded: value ^ mask)
}