function _getStats(uri) {
        return new FileSystemStats({
            isFile: true,
            mtime: SESSION_START_TIME.toISOString(),
            size: 0,
            realPath: uri,
            hash: uri
        });
    }
Create a new file stat. See the FileSystemStats class for more details.

@param {!string} fullPath The full path for this File.
@return {FileSystemStats} stats.