Library in the Eventide toolkit. When passed a class, `Mimic` returns an object that implements that class's interface but does nothing — an implementation of the null-object pattern. Instances are inert by default and can be told to `:record` so tests can ask them whether/how they were interacted with (e.g. `http_client.invoked?(:post)`). Bellware frames mimic substitutes explicitly as *not* mock objects: they are part of the design, not transparency retrofitted onto test files. Used by Eventide components to default their dependencies to substitutable null implementations, so objects are 'useful' immediately on initialization without nil-reference errors.