* {@code function} to the argument, then evaluating using {@code this}. That is, for any pair of
   * non-null objects {@code x} and {@code y}, {@code equivalence.onResultOf(function).equivalent(a,
   * b)} is true if and only if {@code equivalence.equivalent(function.apply(a), function.apply(b))}
   * is true.
   *
   * <p>For example:
   *
   * <pre>{@code