presto-orc/src/main/java/io/prestosql/orc/stream/InputStreamSources.java/InputStreamSources/InputStreamSources
class InputStreamSources:    public InputStreamSources(Map<StreamId, InputStreamSource<?>> streamSources)
    {
        this.streamSources = ImmutableMap.copyOf(requireNonNull(streamSources, "streamSources is null"));
    }