Boost.MultiIndex refactored

Boost.MultiIndex was launched as part of Boost 1.32 in November 2004. The library is still actively maintained and in use by some notable projects such as BitcoinCore , CERN ATLAS , ClickHouse , Folly and Redpanda , to name a few. Back in 2004, variadic templates and typelists were emulated in C++03 with the help of libraries like Boost.Preprocessor and Boost.MPL . These libraries were ground…