nullable: true
                          type: boolean
                        allowHeaders:
                          description: List of HTTP headers that can be used when
                            requesting the resource.
                          items:
                            type: string
                          type: array

                          nullable: true
                          type: boolean
                        allowHeaders:
                          description: List of HTTP headers that can be used when
                            requesting the resource.
                          items:
                            type: string
                          type: array

    It significantly reduces the peak memory required and latency incurred
    during restore.
*   Added a new library for library of matrix-free (iterative) solvers for
    linear equations, linear least-squares, eigenvalues and singular values in
    tensorflow/contrib/solvers. Initial version has lanczos bidiagonalization,
    conjugate gradients and CGLS.
*   Added gradients for `matrix_solve_ls` and `self_adjoint_eig`.