[boost] Re: Release 1.33 [serialization] [variant]

One question, as I'm not familiar with the serialization library. What effect do the proposed changes have on those users of variant who do not need/want serialization support? Obviously there is the addition #include, but does this imply overhead, or is the header simply forward declares in the spirit of <iosfwd>?

Implement everything in separate header (f.e. boost/variant/serialization.hpp) and there wouldn't be any cost for people who don't need that Gennadiy