sourceafIoc::ServiceId.fan

** An optional facet to use in conjunction with [@Inject]`Inject` to specify a service to inject. 
** Use when a service mixin has multiple implementations.
** 
** pre>
** @Inject @ServiceId { id = "impl2" }
** MyService myService
** <pre
** 
** May not be used with '@Autobuild' or other [Dependency Providers]`DependencyProvider`.
** 
** @since 1.1.0
facet class ServiceId {
    const Str id
}