@Override
    public void close() throws Exception {
        beginShutdown();
        eventQueue.close();
    }
Remove a publisher and close it.

@param publisher         The publisher to remove and close.

@return                  A future which yields null when the publisher has been removed
                         and closed, or an exception if the removal failed.
metadata/src/main/java/org/apache/kafka/image/loader/MetadataLoader.java