libboost-type-erasure1.71-dev 1.71.0-2 (amd64 binary) in ubuntu focal

 This package forms part of the Boost C++ Libraries collection.
 .
 C++ has two distinct kinds of polymorphism, virtual functions and templates,
 each of which has its own advantages and disadvantages. The Boost.TypeErasure
 library combines the superior abstraction capabilities of templates, with the
 runtime flexibility of virtual functions.