v0.3.1

• Gen::forClass() names the chain that reached a class it cannot instantiate:
  Cannot generate …\Duration: it is not instantiable (reached through …\BreakerConfig -> …\Ratio -> …\Duration). A value object with a private
  constructor and named factories is usually several levels below the class you
  asked for, and naming only that class sent the reader hunting for which
  parameter pulled it in — the cycle and depth refusals already named their
  chains. Found by using forClass() on a real package rather than on a
  fixture.