// part of the line returned by ReadLine.
func (b *Reader) ReadLine() (line []byte, isPrefix bool, err error) {
	line, err = b.ReadSlice('\n')
	if err == ErrBufferFull {
		// Handle the case where "\r\n" straddles the buffer.
		if len(line) > 0 && line[len(line)-1] == '\r' {
			// Put the '\r' back on buf and drop it from line.
			// Let the next call to ReadLine check for "\r\n".
			if b.r == 0 {

func (b *Buffer) ReadBytes(delim byte) (line []byte, err error) {
	slice, err := b.readSlice(delim)
	// return a copy of slice. The buffer's backing array may
	// be overwritten by later calls.
	line = append(line, slice...)
	return line, err
}

// readSlice is like ReadBytes but returns a reference to internal buffer data.
func (b *Buffer) readSlice(delim byte) (line []byte, err error) {
	i := IndexByte(b.buf[b.off:], delim)

		(*Reader).ReadBytes,
		(*Reader).ReadSlice,
		func(r *Reader, delim byte) ([]byte, error) {
			data, err := r.ReadString(delim)
			return []byte(data), err
		},
		// ReadLine doesn't fit the data/pattern easily
		// so we leave it out. It should be covered via
		// the ReadSlice test since ReadLine simply calls
		// ReadSlice, and it's that function that handles
		// the last byte.
	}

// The returned bytes are owned by the bufio.Reader
// so they are only valid until the next bufio read.
func readChunkLine(b *bufio.Reader) ([]byte, []byte, error) {
	buf, err := b.ReadSlice('\n')
	if err != nil {
		// We always know when EOF is coming.
		// If the caller asked for a line, there should be a line.
		if err == io.EOF {
			err = io.ErrUnexpectedEOF
		} else if err == bufio.ErrBufferFull {

  /** Read a single line counted against the header size limit. */
  fun readLine(): String {
    val line = source.readUtf8LineStrict(headerLimit)
    headerLimit -= line.length.toLong()
    return line
  }

  /** Reads headers or trailers. */
  fun readHeaders(): Headers {
    val result = Headers.Builder()
    while (true) {
      val line = readLine()
      if (line.isEmpty()) break
      result.addLenient(line)
    }

      return reader.readLine();
    } catch (Throwable e) {
      throw closer.rethrow(e);
    } finally {
      closer.close();
    }
  }

  /**
   * Reads all the lines of this source as a list of strings. The returned list will be empty if
   * this source is empty.
   *
   * <p>Like {@link BufferedReader#readLine()}, this method considers a line to be a sequence of

    val reader = BufferedReader(InputStreamReader(connection.inputStream, UTF_8))
    assertThat(connection.responseCode).isEqualTo(HttpURLConnection.HTTP_OK)
    assertThat(reader.readLine()).isEqualTo("hello world")
    val request = server.takeRequest()
    assertThat(request.requestLine).isEqualTo("GET / HTTP/1.1")
    assertThat(request.headers["Accept-Language"]).isEqualTo("en-US")

    val reader = BufferedReader(InputStreamReader(inputStream, StandardCharsets.UTF_8))
    assertThat(connection.getResponseCode()).isEqualTo(HttpURLConnection.HTTP_OK)
    assertThat(reader.readLine()).isEqualTo("hello world")
    val request = server.takeRequest()
    assertThat(request.requestLine).isEqualTo("GET / HTTP/1.1")
    assertThat(request.getHeader("Accept-Language")).isEqualTo("en-US")

     * @return 一行の文字列。終端に達した場合は{@literal null}
     * @see BufferedReader#readLine()
     */
    public static String readLine(final BufferedReader reader) {
        assertArgumentNotNull("reader", reader);

        try {
            return reader.readLine();
        } catch (final IOException e) {
            throw new IORuntimeException(e);
        }
    }

    /**

import java.util.ArrayDeque;
import java.util.Queue;
import javax.annotation.CheckForNull;

/**
 * A class for reading lines of text. Provides the same functionality as {@link
 * java.io.BufferedReader#readLine()} but for all {@link Readable} objects, not just instances of
 * {@link Reader}.
 *
 * @author Chris Nokleberg
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault