26 std::variant<BoundMatrix, BoundToFreeMatrix, FreeToBoundMatrix, FreeMatrix>;
101 std::tuple<VariantCovariance, VariantTransportJacobian>
110 std::tuple<VariantCovariance, VariantTransportJacobian>
117 std::tuple<VariantCovariance, VariantTransportJacobian>