@Override
    public String toString() {
        return StringFactory.storageString(this.fs.toString());
    }
@param pattern refers directory or a set of files
@return a non-null array of the files and directories the pattern refers as of {@link Storage#ls(String)}
hadoop-gremlin/src/main/java/org/apache/tinkerpop/gremlin/hadoop/structure/io/FileSystemStorage.java