if err != nil {
			t.Fatalf("Part %d: ReadAll failed: %v", i, err)
		}
		i++
	}

	readPart(textproto.MIMEHeader{"Foo-Bar": {"baz"}}, "Body")

	select {
	case <-done1:
		t.Errorf("Reader read past second boundary")
	default:
	}

	readPart(textproto.MIMEHeader{"Foo-Bar": {"bop"}}, "Body 2")
}

func TestLineContinuation(t *testing.T) {

type parallelReader struct {
	readers       []io.ReaderAt
	orgReaders    []io.ReaderAt
	dataBlocks    int
	offset        int64
	shardSize     int64
	shardFileSize int64
	buf           [][]byte
	readerToBuf   []int
	stashBuffer   []byte
}

// newParallelReader returns parallelReader.
func newParallelReader(readers []io.ReaderAt, e Erasure, offset, totalLength int64) *parallelReader {

		return 0, io.EOF
	}
	r.prevRune = -1
	n = copy(b, r.s[r.i:])
	r.i += int64(n)
	return
}

// ReadAt implements the [io.ReaderAt] interface.
func (r *Reader) ReadAt(b []byte, off int64) (n int, err error) {
	// cannot modify state - see io.ReaderAt
	if off < 0 {
		return 0, errors.New("strings.Reader.ReadAt: negative offset")
	}
	if off >= int64(len(r.s)) {
		return 0, io.EOF
	}
	n = copy(b, r.s[off:])

			return fmt.Errorf("ReadAt(%d, 0) = %q\n\twant %q", len(data), data, content)
		}

		n, err = r.ReadAt(data[:1], int64(len(data)))
		if n != 0 || err != io.EOF {
			return fmt.Errorf("ReadAt(1, %d) = %v, %v, want 0, EOF", len(data), n, err)
		}

		for i := range data {
			data[i] = 0xfe
		}
		n, err = r.ReadAt(data[:cap(data)], 0)
		if n != len(data) || err != io.EOF {

		t.Fatal("Seek:", off)
	}

	// Use ReadAt to read the entire file, ignoring the offset.
	at := file.(io.ReaderAt)
	got = make([]byte, len(want))
	n, err = at.ReadAt(got, 0)
	if err != nil {
		t.Fatal("ReadAt:", err)
	}
	if n != len(want) {
		t.Fatalf("ReadAt: got %d bytes, want %d bytes", n, len(want))
	}
	if string(got) != want {
		t.Fatalf("ReadAt: got %q, want %q", got, want)
	}

//
// If ReadAt is reading from an input source with a seek offset,
// ReadAt should not affect nor be affected by the underlying
// seek offset.
//
// Clients of ReadAt can execute parallel ReadAt calls on the
// same input source.
//
// Implementations must not retain p.
type ReaderAt interface {
	ReadAt(p []byte, off int64) (n int, err error)
}

// WriterAt is the interface that wraps the basic WriteAt method.
//

type Section struct {
	SectionHeader
	Relocs []Reloc

	// Embed ReaderAt for ReadAt method.
	// Do not embed SectionReader directly
	// to avoid having Read and Seek.
	// If a client wants Read and Seek it must use
	// Open() to avoid fighting over the seek offset
	// with other clients.
	io.ReaderAt
	sr *io.SectionReader
}

// Data reads and returns the contents of the PE section s.
//

type Section struct {
	SectionHeader

	// Embed ReaderAt for ReadAt method.
	// Do not embed SectionReader directly
	// to avoid having Read and Seek.
	// If a client wants Read and Seek it must use
	// Open() to avoid fighting over the seek offset
	// with other clients.
	io.ReaderAt
	sr *io.SectionReader
}

// Data reads and returns the contents of the Plan 9 a.out section.

func ReadDataAt(r io.ReaderAt, n uint64, off int64) ([]byte, error) {
	if int64(n) < 0 || n != uint64(int(n)) {
		// n is too large to fit in int, so we can't allocate
		// a buffer large enough. Treat this as a read failure.
		return nil, io.ErrUnexpectedEOF
	}

	if n < chunk {
		buf := make([]byte, n)
		_, err := r.ReadAt(buf, off)
		if err != nil {

// This is only safe because there won't be any concurrent seeks
// while this code is executing.
func readerAtFromSeeker(rs io.ReadSeeker) io.ReaderAt {
	if ret, ok := rs.(io.ReaderAt); ok {
		return ret
	}
	return seekerReadAt{rs}
}

type seekerReadAt struct {
	seeker io.ReadSeeker
}

func (sra seekerReadAt) ReadAt(p []byte, off int64) (int, error) {