if err := cfw.writeHeader(metaFileHash); err != nil {
		return err
	}
	return cfw.AppendSegment(args, visitor)
}

func padToFourByteBoundary(ws *slicewriter.WriteSeeker) error {
	sz := len(ws.BytesWritten())
	zeros := []byte{0, 0, 0, 0}
	rem := uint32(sz) % 4
	if rem != 0 {
		pad := zeros[:(4 - rem)]
		if nw, err := ws.Write(pad); err != nil {
			return err

	log.SetPrefix("emitToWriter: ")
	var slwm slicewriter.WriteSeeker
	if err := coverage.WriteMeta(&slwm); err != nil {
		log.Fatalf("error: WriteMeta returns %v", err)
	}
	mf := filepath.Join(*outdirflag, "covmeta.0abcdef")
	if err := os.WriteFile(mf, slwm.BytesWritten(), 0666); err != nil {
		log.Fatalf("error: writing %s: %v", mf, err)
	}
	var slwc slicewriter.WriteSeeker
	if err := coverage.WriteCounters(&slwc); err != nil {

	nFuncs := len(b.funcs)
	var foff int64 = coverage.CovMetaHeaderSize + int64(b.stab.Size()) + int64(nFuncs)*4
	for idx := 0; idx < nFuncs; idx++ {
		b.wrUint32(w, uint32(foff))
		foff += int64(len(b.funcs[idx].encoded))
	}
	return off + (int64(len(b.funcs)) * 4)
}

func (b *CoverageMetaDataBuilder) emitFunc(w io.WriteSeeker, off int64, f funcDesc) (int64, error) {

// ReadSeekCloser is the interface that groups the basic Read, Seek and Close
// methods.
type ReadSeekCloser interface {
	Reader
	Seeker
	Closer
}

// WriteSeeker is the interface that groups the basic Write and Seek methods.
type WriteSeeker interface {
	Writer
	Seeker
}

// ReadWriteSeeker is the interface that groups the basic Read, Write and Seek methods.
type ReadWriteSeeker interface {
	Reader

	fh := md5.New()
	blobs := [][]byte{}
	tlen := uint64(unsafe.Sizeof(coverage.MetaFileHeader{}))
	for _, p := range mm.pkgs {
		var blob []byte
		if pcombine {
			mdw := &slicewriter.WriteSeeker{}
			p.cmdb.Emit(mdw)
			blob = mdw.BytesWritten()
		} else {
			blob = p.mdblob
		}
		ph := md5.Sum(blob)
		blobs = append(blobs, blob)
		if _, err := fh.Write(ph[:]); err != nil {

	}
	return n, err
}

// writeTo writes the content of the current file to w.
// The bytes written matches the number of remaining bytes in the current file.
//
// If the current file is sparse and w is an io.WriteSeeker,
// then writeTo uses Seek to skip past holes defined in Header.SparseHoles,
// assuming that skipped regions are filled with NULs.
// This always writes the last byte to ensure w is the right size.
//

	for k := range p.counterLengths {
		cvn := mkCounterVarName(k)
		fmt.Fprintf(w, "var %s [%d]uint32\n", cvn, p.counterLengths[k])
	}

	// Emit encoded meta-data.
	var sws slicewriter.WriteSeeker
	digest, err := p.mdb.Emit(&sws)
	if err != nil {
		log.Fatalf("encoding meta-data: %v", err)
	}
	p.mdb = nil
	fmt.Fprintf(w, "var %s = [...]byte{\n", mkMetaVar())
	payload := sws.BytesWritten()

		{"SeekCurrent", Const, 7},
		{"SeekEnd", Const, 7},
		{"SeekStart", Const, 7},
		{"Seeker", Type, 0},
		{"StringWriter", Type, 12},
		{"TeeReader", Func, 0},
		{"WriteCloser", Type, 0},
		{"WriteSeeker", Type, 0},
		{"WriteString", Func, 0},
		{"Writer", Type, 0},
		{"WriterAt", Type, 0},
		{"WriterTo", Type, 0},
	},
	"io/fs": {
		{"(*PathError).Error", Method, 16},