@Override
 public long openUfsFile(long sessionId, AlluxioURI ufsUri)
     throws FileDoesNotExistException, IOException {
   return mUnderFileSystemManager.openFile(sessionId, ufsUri);
 }
 @Override
 public OutputStream getUfsOutputStream(long tempUfsFileId) throws FileDoesNotExistException {
   return mUnderFileSystemManager.getOutputStream(tempUfsFileId);
 }
 @Override
 public InputStream getUfsInputStream(long tempUfsFileId, long position)
     throws FileDoesNotExistException, IOException {
   return mUnderFileSystemManager.getInputStreamAtPosition(tempUfsFileId, position);
 }
 @Override
 public long createUfsFile(long sessionId, AlluxioURI ufsUri, Permission perm)
     throws FileAlreadyExistsException, IOException {
   return mUnderFileSystemManager.createFile(sessionId, ufsUri, perm);
 }
 @Override
 public long completeUfsFile(long sessionId, long tempUfsFileId, Permission perm)
     throws FileDoesNotExistException, IOException {
   return mUnderFileSystemManager.completeFile(sessionId, tempUfsFileId, perm);
 }
 @Override
 public void closeUfsFile(long sessionId, long tempUfsFileId)
     throws FileDoesNotExistException, IOException {
   mUnderFileSystemManager.closeFile(sessionId, tempUfsFileId);
 }