List<NamedReader> getAllDataFromDirectory(Path path, String fileNameSuffix, boolean recursive) {
        return getAllDataFromDirectory(path, "", fileNameSuffix, recursive);
    }
Returns a list of the files (as readers) in the given path. The readers <b>must</b>
be closed by the caller.

@param path           a path relative to the session
                      (i.e. /config/v2/tenants/x/sessions/&lt;session id&gt;/).
@param fileNameSuffix the suffix of files to return, or null to return all
@param recursive      if true, all files from all subdirectories of this will also be returned
@return the files in the given path, or an empty list if the directory does not exist or is empty.
        The list gets owned by the caller and can be modified freely.
configserver/src/main/java/com/yahoo/vespa/config/server/zookeeper/ZKApplication.java