/// <summary>
 /// Initializes a new instance of the <see cref="StreamProcessorStateRepository"/> class.
 /// </summary>
 /// <param name="streamProcessorStates">The <see cref="IStreamProcessorStates" />.</param>
 /// <param name="subscriptionStates">The <see cref="ISubscriptionStates" />.</param>
 /// <param name="logger">An <see cref="ILogger"/>.</param>
 public StreamProcessorStateRepository(
     IStreamProcessorStates streamProcessorStates,
     ISubscriptionStates subscriptionStates,
     ILogger logger)
 {
     _streamProcessorStates = streamProcessorStates;
     _subscriptionStates    = subscriptionStates;
     _streamProcessorFilter = Builders <AbstractStreamProcessorState> .Filter;
     _subscriptionFilter    = Builders <MongoSubscriptionState> .Filter;
     _logger = logger;
 }