@Override
    public void close() throws IOException { }
An implementation of {@link ConfigProvider} based on a directory of files.
Property keys correspond to the names of the regular (i.e. non-directory)
files in a directory given by the path parameter.
Property values are taken from the file contents corresponding to each key.
clients/src/main/java/org/apache/kafka/common/config/provider/DirectoryConfigProvider.java