...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
The type for each element in the list of buffers.
using value_type = typename std::conditional< std::is_convertible< typename std::iterator_traits< iter_type >::value_type, boost::asio::mutable_buffer >::value, boost::asio::mutable_buffer, boost::asio::const_buffer >::type;