SubSinkInlet

INTERNAL API

This allows the dynamic creation of an Inlet for a GraphStage which is connected to a Sink that is available for materialization (e.g. using the subFusingMaterializer). Completion, cancellation and failure of the parent operator is automatically delegated to instances of SubSinkInlet to avoid resource leaks.

To be thread safe this method must only be called from either the constructor of the graph operator during materialization or one of the methods invoked by the graph operator machinery, such as onPush and onPull.