After calling Abort(Exception) the running instance of the IGraphTShape of FlowShapeTIn, TOut that materialized to the UniqueKillSwitch will fail its downstream with the provided exception and cancel its upstream (unless if finished or failed already in which case the command is ignored). Subsequent invocations of completion commands will be ignored.

public void Abort(
	Exception cause
)

abstract Abort : 
        cause : Exception -> unit 
override Abort : 
        cause : Exception -> unit