An easy to use mockable clock. Pass WallClock to your services in production/dev code and use MockClock in unit tests; or, if you don't want to pass around a clock, do Clock.Default = new MockClock(); in your unit tests.
Provides the ability to configure Autofac with behavior that will dynamically intercept concrete classes marked with
`FreezeTimeAttribute` such that resolved `IClock` instances will reflect a frozen instance in time time, throughout
the duration of each intercepted call.