this.file = file;
    }

    /**
     * Update the file ID after successful create response
     * @param newFileId the new 16-byte file ID
     */
    public void updateFileId(byte[] newFileId) {
        if (newFileId.length != 16) {
            throw new IllegalArgumentException("File ID must be 16 bytes");
        }
        System.arraycopy(newFileId, 0, this.fileId, 0, 16);
    }