 implementation of this algorithm is not only quite complex
  but also much slower than the simplified version employed by
  Boost.Statechart, which stops searching for <a href=
  "definitions.html#Reaction">reactions</a> as soon as it has found one
  suitable for the current event. That is, had the example been implemented
  with this library, the machine would have transitioned
  non-deterministically from (B,D) to either (C,D) or (B,E). This version was
  chosen because, in my experience, in real-world m