presto-main/src/main/java/io/prestosql/split/BufferingSplitSource.java/BufferingSplitSource/BufferingSplitSource
class BufferingSplitSource:    public BufferingSplitSource(SplitSource source, int bufferSize)
    {
        this.source = requireNonNull(source, "source is null");
        this.bufferSize = bufferSize;
    }