@Override
        public Provisioner getProvisioner(final int unicastAddress) {
            for (Provisioner provisioner : mMeshNetwork.getProvisioners()) {
                if (provisioner.isLastSelected())
                    return provisioner;
            }
            return null;
        }
Updates the minimum security property of a Network Key. If the node was provisioned
insecurely, all network keys added to the node are marked as insecure.

@param node Provisioned mesh node.
mesh/src/main/java/no/nordicsemi/android/mesh/MeshManagerApi.java