// Write a version for making *incompatible* changes.
	// The AdminClient will reject any version it does not know.
	var inspectZipW *zip.Writer
	if publicKey != nil {
		w.WriteHeader(200)
		stream := estream.NewWriter(w)
		defer stream.Close()

		clusterKey, err := bytesToPublicKey(getSubnetAdminPublicKey())
		if err != nil {
			bugLogIf(ctx, stream.AddError(err.Error()))
			return
		}

		go func() {
			// Initialize MRF meta header.
			var data [4]byte
			binary.LittleEndian.PutUint16(data[0:2], mrfMetaFormat)
			binary.LittleEndian.PutUint16(data[2:4], mrfMetaVersion)
			mw := msgp.NewWriter(w)
			n, err := mw.Write(data[:])
			if err != nil {
				w.CloseWithError(err)
				return
			}
			if n != len(data) {
				w.CloseWithError(io.ErrShortWrite)
				return
			}