[ ] Combiners use push model instead of pull model - see Combiner Interface in Boost docs
[ ] Combiners are template template parameters - see #2
[ ] Boost.Signals2 default combiner returns boost::optional<T> - in FastSignals, it returns std::optional<T>
[ ] Slot return type never ignored for signals - in other words, you cannot return bool in slot connected to void(...) signal
[x] Boost.Signals2 includes <map>, <boost/noncopyable.hpp>, <boost/scoped_ptr.hpp>, <boost/variant/variant.hpp>, <boost/optional/optional.hpp> - FastSignals does not
boost::optional<T>- in FastSignals, it returnsstd::optional<T>boolin slot connected tovoid(...)signal<map>,<boost/noncopyable.hpp>,<boost/scoped_ptr.hpp>,<boost/variant/variant.hpp>,<boost/optional/optional.hpp>- FastSignals does not