we require.  Deriving from
the base class <a href="../../../boost/archive/detail/common_oarchive.hpp" target="common_oarchive_hpp">
common_oarchive.hpp</a> provides all features we desire which
are missing from trivial_oarchive above.

<pre><code>
<a href="../../../boost/archive/detail/common_oarchive.hpp" target="common_oarchive_hpp">
#include &lt;cstddef&gt; // std::size_t
#include &lt;boost/archive/detail/common_oarchive.hpp&gt;
</a>
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