registerSingleton<T> method
registers a type as Singleton by passing an instance of that type
that will be returned on each call of get on that type
T type to register
instanceName if you provide a value here your instance gets registered with that
name instead of a type. This should only be necessary if you need to register more
than one instance of one type. Its highly not recommended
If signalsReady is set to true it means that the future you can get from allReady()
cannot complete until this this instance was signalled ready by calling signalsReady(instance).
Implementation
void registerSingleton<T>(T instance,
{String instanceName, bool signalsReady});