public void Open(string fileName)
        {
            var indexFile = IsobaricResultXmlIndexBuilder.GetTargetFile(fileName);

            if (!File.Exists(indexFile))
            {
                new IsobaricResultXmlIndexBuilder()
                {
                    Progress = this.Progress
                }.Process(fileName);
            }

            Progress.SetMessage("Reading index from " + indexFile + " ...");
            this._indexItems = new FileIndexFormat().ReadFromFile(indexFile).ToDictionary(m => m.Key);
            Progress.SetMessage("Reading index from " + indexFile + " finished.");

            this._stream = FileUtils.OpenReadFile(fileName);
        }