public FileHierarchyDirectoryNode AddDirectory(string subdirectory)
 {
     var pathToDirectory = Path.Combine(this.fullDirectoryPath, subdirectory);
     var builderNode = new FileHierarchyDirectoryNode(pathToDirectory);
     this.children.Add(builderNode);
     return builderNode;
 }
        public FileHierarchyDirectoryNode AddDirectory(string subdirectory)
        {
            var pathToDirectory = Path.Combine(this.fullDirectoryPath, subdirectory);
            var builderNode     = new FileHierarchyDirectoryNode(pathToDirectory);

            this.children.Add(builderNode);
            return(builderNode);
        }