@Override
  public synchronized void initialize(URI uri, org.apache.hadoop.conf.Configuration conf)
      throws IOException {
    initialize(uri, conf, null);
  }
@ Override public synchronized void initialize ( URI uri , org . apache . hadoop . conf . Configuration conf ) throws IOException { initialize ( uri , conf , null ) ; }
{@inheritDoc}

Sets up a lazy connection to Alluxio through mFileSystem. This must be called before client
operations.

If it is called twice on the same object concurrently, one of the thread will do the
initialization work, the other will wait until initialization is done.
If it is called after initialized, then this is a noop.