public void merge(RoutingContext ctx) {
        throw new AssertionError("Routing should not pass terminated selection.");
    }
Creates a new policy that will assign an {@link EmptyReply} with the given error to all routing contexts that
invoke {@link #select(RoutingContext)}.

@param msg The message of the error to assign.
documentapi/src/main/java/com/yahoo/documentapi/messagebus/protocol/ErrorPolicy.java