/** Asset storage object. Assets are binary files attached to a node.
 * Use `node.createAsset()` to create an asset object. Asset objects have
 * minimal meta information about the asset file: just subtype and
 * file extension. All other metadata should be stored in the node it
 * is attached to.
 *
 * @class Asset
 * @memberof jibo.kb
 * @param {string} [filenameOrUrl] Filename to asset on disk, or url
 * to asset via KB service.
 * @param {string} [subtype] Subtype name of asset. Defaults to `asset`.
 * @param {string} [ext] Optional filename extension.
 */

    /** Create an Error with a good message from an AxiosError object
     *
     * @method jibo.kb.KnowledgeBase#_processError
     * @param {AxiosError} err Axios error object.
     * @returns {Error} Error object.
     * @private
     */

    /** The filename for this asset, without any directory
     * information. Format of the filename is:
     *
     * `{$_id}.{$subtype}.{$ext}`.
     *
     * If the asset doesn't have an extension, `{$ext}` (and its dot
     * seperator) will be absent.
     *
     * @method jibo.kb.Asset#filename
     * @returns {string} The filename.
     */

    /** Full path to the asset file on disk or a URL to fetch it
     * via the KB service.
     *
     * @method jibo.kb.Asset#fullFilenameOrURL
     * @returns {string} Full path filename or URL.
     */

    /** Print useful console logs from asset objects.
     *
     * @method jibo.kb.Asset#toString
     * @returns {string} Full path filename or URL.
     */

    /** Write out the data for this asset file. Data can be provided
     * as a readable stream, buffer, or blob.
     *
     * @method jibo.kb.Asset#save
     * @param {stream.Readable|Buffer|Blob} data Data to be saved in asset file.
     * @param {Function} [callback] Called when done. If callback is
     * omitted a promise is returned instead.
     * @returns {Promise} A promise if the callback is omitted.
     */

    /** Set up an asset object by parsing an asset filename or
     * URL. Sets the `_id`, `subtype`, and `ext`. Set rootDir if full
     * path filename or URL.
     *
     * @method jibo.kb.Asset#setSelfFromFilenameOrURL
     * @param {string} filenameOrUrl Filename, full path filename, or URL.
     */

    /** Load the binary file pointed to by this asset object.
     * Returns a buffer (via callback) with the contents (data) of the file.
     *
     * @method jibo.kb.Asset#load
     * @param {Function} [callback] Called with (err, data) when
     * done. If callback is omitted a promise that resolves to `data`
     * is returned instead.
     * @returns {Promise} A promise that resolves with the value of
     * `data` if the callback is omitted.
     */

    /** Create a stream of the binary file this asset object points to.
     * Return a stream (via callback) of the contents (data)
     * of the file.
     *
     * @method jibo.kb.Asset#loadStream
     * @returns {Promise<stream.Readable>} Stream of binary asset data.
     */

    /** Load the binary file pointed to by this asset object.
     * Returns a blob (via callback) with the contents (data) of the file.
     *
     * @method jibo.kb.Asset#loadBlob
     * @param {Function} [callback] Called with (err, data) when
     * done. If callback is omitted a promise that resolves to `data`
     * is returned instead.
     * @returns {Promise} A promise that resolves with the value of
     * `data` if the callback is omitted.
     */

    /** Remove the asset file from disk.
     *
     * @method jibo.kb.Asset#remove
     * @param {Function} [callback] Called when done. If callback is
     * omitted a promise is returned instead.
     * @returns {Promise} A promise if the callback is omitted.
     */

    /** Assemble the URL for this asset.
     *
     * @method jibo.kb.Asset#_url
     * @returns {string} URL
     * @private
     */

    /** Saves the asset data via the KB service web interface.
     *
     * @method jibo.kb.Asset#_saveViaWeb
     * @private
     */

    /** Set up an asset by parsing a filename
     *
     * @method jibo.kb.Asset#_setSelfFromFilename
     * @param {string} filename Filename or full path filename
     * @private
     */

    /** Set up an asset from a URL
     *
     * @method jibo.kb.Asset#_setSelfFromURL
     * @param {string} URL
     * @private
     */

    /** Remove the asset file from disk via KB service.
     *
     * @method jibo.kb.Asset#_removeViaWeb
     * @param {Function} callback Called when done
     * @private
     */

    /** Save asset file from buffer.
     *
     * @method jibo.kb.Asset#_saveBuffer
     * @param {Buffer} buffer Data to be saved in asset file
     * @param {Function} callback Called when done
     * @private
     */

    /** Save asset file from stream.
     *
     * @method jibo.kb.Asset#_saveStream
     * @param {stream.Readable} stream Data to be saved in asset file
     * @param {Function} callback Called when done
     * @private
     */

    /** Loads the asset via the KB service.
     *
     * @method jibo.kb.Asset#_loadBufferViaWeb
     * @param {Function} callback Called with (err, data) when done
     * @private
     */

    /** Loads a stream of the asset via the KB service.
     *
     * @method jibo.kb.Asset#_loadStreamViaWeb
     * @returns {Promise<stream.Readable>} Promise to resolve a Stream of asset
     * @private
     */