function accumulate0d( x, initial, clbk ) {
	return clbk( initial, x.data[ x.offset ] );
}
Performs a reduction over elements in a zero-dimensional input ndarray.

@private
@param {Object} x - object containing input ndarray meta data
@param {string} x.dtype - data type
@param {Collection} x.data - data buffer
@param {NonNegativeIntegerArray} x.shape - dimensions
@param {IntegerArray} x.strides - stride lengths
@param {NonNegativeInteger} x.offset - index offset
@param {string} x.order - specifies whether `x` is row-major (C-style) or column-major (Fortran-style)
@param {*} initial - initial value
@param {Callback} clbk - callback function
@returns {*} result

@example
var Float64Array = require( '@stdlib/array/float64' );

function add( acc, x ) {
    return acc + x;
}

// Create a data buffer:
var xbuf = new Float64Array( [ 1.0, 2.0 ] );

// Define the shape of the input array:
var shape = [];

// Define the array strides:
var sx = [ 0 ];

// Define the index offset:
var ox = 1;

// Create the input ndarray-like object:
var x = {
    'dtype': 'float64',
    'data': xbuf,
    'shape': shape,
    'strides': sx,
    'offset': ox,
    'order': 'row-major'
};

// Compute the sum:
var v = accumulate0d( x, 0.0, add );
// returns 2.0