[boost] Proposed for inclusion in boost: a C++11 span

Dear all, I started to work on a C++11 implementation of std::span. The interface will be an exact mirror of std::span, https://en.cppreference.com/w/cpp/container/span. Having a drop-in replacement of std::span for systems with older compilers in Boost seems like a very good idea. Is anyone else already working on this? I am happy to join forces. Coding down the span took me an hour, but several more hours will go into unit testing and documenting. Best regards, Hans