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
			}