private void applyToEachBuilder(final Consumer<InternalTopologyBuilder> function) {
        for (final InternalTopologyBuilder builder : builders.values()) {
            function.accept(builder);
        }
    }
@return the InternalTopologyBuilder for the NamedTopology with the given {@code topologyName}
        or the builder for a regular Topology if {@code topologyName} is {@code null},
        else returns {@code null} if {@code topologyName} is non-null but no such NamedTopology exists
streams/src/main/java/org/apache/kafka/streams/processor/internals/TopologyMetadata.java