How to get the average of several chrono::time_points : <p>The formula for getting the average of several numbers is of course well known:</p>

<p><img src="https://latex.codecogs.com/gif.latex?avg%20%3D%20%5Cfrac%7B%5Csum_%7Bi%3D1%7D%5EN%20x_i%7D%7BN%7D" alt=""></p>

<p>And this formula can easily be used to get the average of <code>chrono::duration</code>s:</p>

<pre><code>template &lt;class Rep0, class Period0&gt;
auto
sum(const std::chrono::duration&lt;Rep0, Period0&gt;&amp; d0)
{
    return d0;
}

template &lt;class Rep0, class Period0, class ...Rep, class ...Period&gt;
auto
sum(const std::chrono::duration&lt;Rep0, Period0&gt;&amp; d0,
    const std::chrono::duration&lt;Rep, Period&gt;&amp; ...d)
{
    return d0 + sum(d...);
}

template &lt;class ...Rep, class ...Period&gt;
auto
avg(const std::chrono::duration&lt;Rep, Period&gt;&amp; ...d)
{
    return sum(d...) / sizeof...(d);
}
</code></pre>

<p>But <code>chrono::time_point</code>s can't be added to one another.  How can I average <code>time_point</code>s?</p>
