import (
	"errors"
	"io"
	"unicode/utf8"
)

// A Reader implements the [io.Reader], [io.ReaderAt], [io.WriterTo], [io.Seeker],
// [io.ByteScanner], and [io.RuneScanner] interfaces by reading from
// a byte slice.
// Unlike a [Buffer], a Reader is read-only and supports seeking.
// The zero value for Reader operates like a Reader of an empty slice.
type Reader struct {
	s        []byte
	i        int64 // current reading index

// AWS Signature V4 chunked reader.
type s3UnsignedChunkedReader struct {
	reader   *bufio.Reader
	trailers http.Header

	buffer []byte
	offset int
	err    error
	debug  bool
}

func (cr *s3UnsignedChunkedReader) Close() (err error) {
	return cr.err
}

// Read - implements `io.Reader`, which transparently decodes
// the incoming AWS Signature V4 streaming signature.

)

var magicHeaders = []struct {
	header []byte
	f      format
}{
	{
		header: []byte{0x1f, 0x8b, 8},
		f:      formatGzip,
	},
	{
		// Zstd default header.
		header: []byte{0x28, 0xb5, 0x2f, 0xfd},
		f:      formatZstd,
	},
	{
		// Zstd skippable frame header.
		header: []byte{0x2a, 0x4d, 0x18},
		f:      formatZstd,
	},
	{
		// LZ4
		header: []byte{0x4, 0x22, 0x4d, 0x18},

        addDocument(indexName, client, num);

        ESSourceReader reader = new ESSourceReader(client, settings, indexName);
        reader.setScrollSize(1);
        reader.setLimitDocNumPercentage("1%");
        int count = 0;
        Set<String> valueSet = Collections.synchronizedSet(new HashSet<>());
        Map<String, Object> source;
        while ((source = reader.read()) != null) {

    CharSequenceReader reader = new CharSequenceReader(string);
    assertTrue(reader.markSupported());

    assertEquals(string, readFully(reader));
    assertFullyRead(reader);

    // reset and read again
    reader.reset();
    assertEquals(string, readFully(reader));
    assertFullyRead(reader);

    // reset, skip, mark, then read the rest
    reader.reset();
    assertEquals(5, reader.skip(5));

) : DerAdapter<T> {
  init {
    require(tagClass >= 0)
    require(tag >= 0)
  }

  override fun matches(header: DerHeader): Boolean = header.tagClass == tagClass && header.tag == tag

  override fun fromDer(reader: DerReader): T {
    val peekedHeader = reader.peekHeader()
    if (peekedHeader == null || peekedHeader.tagClass != tagClass || peekedHeader.tag != tag) {
      if (isOptional) return defaultValue as T

	}
}

var UnreadRuneErrorTests = []struct {
	name string
	f    func(*Reader)
}{
	{"Read", func(r *Reader) { r.Read([]byte{0}) }},
	{"ReadByte", func(r *Reader) { r.ReadByte() }},
	{"UnreadRune", func(r *Reader) { r.UnreadRune() }},
	{"Seek", func(r *Reader) { r.Seek(0, io.SeekCurrent) }},
	{"WriteTo", func(r *Reader) { r.WriteTo(&Buffer{}) }},
}

func TestUnreadRuneError(t *testing.T) {

    }

    /**
     * Reads an XML node from a reader.
     */
    @Nonnull
    public static XmlNode read(Reader reader) throws XMLStreamException {
        return read(reader, null);
    }

    /**
     * Reads an XML node from a reader.
     */
    @Nonnull
    public static XmlNode read(Reader reader, @Nullable InputLocationBuilder locationBuilder)

            this.inputStream = inputStream;
            return this;
        }

        public XmlReaderRequestBuilder reader(Reader reader) {
            this.reader = reader;
            return this;
        }

        public XmlReaderRequestBuilder transformer(Transformer transformer) {
            this.transformer = transformer;
            return this;

        normalizeKana = settings.getAsBoolean("normalize_kana", JapaneseIterationMarkCharFilter.NORMALIZE_KANA_DEFAULT);
    }

    @Override
    public Reader create(Reader reader) {
        return new JapaneseIterationMarkCharFilter(reader, normalizeKanji, normalizeKana);
    }