_singleRealTransform2(data, out, outOff, off, step) {
        // radix-2 implementation
        // NOTE: Only called for len=4

        const evenR = data[off];
        const oddR = data[off + step];

        out[outOff] = evenR + oddR;
        out[outOff + 1] = 0;
        out[outOff + 2] = evenR - oddR;
        out[outOff + 3] = 0;
    }
Performs a single real input radix-2 transformation on the provided data

@param {Float64Array} data The input data array
@param {Float64Array} out The output data array
@param {number} outOff The output offset
@param {number} off The input offset
@param {number} step The step

@returns {void}