Registers a block of code (callback) to run after ActorSystem.shutdown has been issued and all actors in this actor system have been stopped. Multiple code blocks may be registered by calling this method multiple times.

The callbacks will be run sequentially in reverse order of registration, i.e. last registration is run first.

Terminates this actor system. This will stop the guardian actor, which in turn will recursively stop all its child actors, then the system guardian (below which the logging actors reside) and the execute all registered termination handlers (RegisterOnTermination(Action)).

Be careful to not schedule any operations on completion of the returned task using the `dispatcher` of this actor system as it will have been shut down before the task completes.

Creates a ActorMaterializer which will execute every step of a transformation pipeline within its own ActorBase. The required IActorRefFactory (which can be either an ActorSystem or an IActorContext) will be used to create one actor that in turn creates actors for the transformation steps.

The materializer's ActorMaterializerSettings will be obtained from the configuration of the context's underlying ActorSystem.

The namePrefix is used as the first part of the names of the actors running the processing steps. The default namePrefix is "flow". The actor names are built up of namePrefix-flowNumber-flowStepNumber-stepName.