function _elementsEqual(a0, a1) {
    let i, ilen, v0, v1;
    if (!a0 || !a1 || a0.length !== a1.length) {
        return false;
    }
    for(i = 0, ilen = a0.length; i < ilen; ++i){
        v0 = a0[i];
        v1 = a1[i];
        if (v0.datasetIndex !== v1.datasetIndex || v0.index !== v1.index) {
            return false;
        }
    }
    return true;
}
Returns true if the `a0` and `a1` arrays have the same content, else returns false.
@param a0 - The array to compare
@param a1 - The array to compare
@private