[lo-simon]

Replace deprecated Boost.Asio functions (buffer_cast/buffer_size, io_service, expires_from_now, reset) with version-gated modern equivalents, ready for use when a newer version of Boost is expected via the newer version of the cpprestsdk

• Use a consistent version-gate pattern (#if BOOST_VERSION >= 106600 ... #else ... #endif) for maintainability and readability across the branch.
• Target the correct Boost version cutoff (1.66.0) - this is indeed when Asio introduced io_context, expires_after()/expires_at(), restart(), and const_buffer::data()/size() as the modern, non-deprecated replacements.
• Preserve backward compatibility with your project's stated minimum Boost version (1.54.0 per NmosCppDependencies.cmake), which is important since older Boost versions don't have these newer APIs at all.
• No behavioural changes - each replacement is a drop-in equivalent for the respective Boost version.

[garethsb]

Looks good. Would it be worth having at least temporarily CI jobs with both older and newer Boost? Or is that too much machinery?

[lo-simon]

Looks good. Would it be worth having at least temporarily CI jobs with both older and newer Boost? Or is that too much machinery?

Let's see what I can do; I think I will need to build cpprestsdk using older Boost without Canon.