protected DeflatedChunksSet createIdatSet(String id){
  return new DeflatedChunksSet(id,1024,1024);
}

protected DeflatedChunksSet createIdatSet ( String id ) { return new DeflatedChunksSet ( id , 1024 , 1024 ) ; }
deflatedchunksset factory . this implementation is quite dummy , it usually should be overriden .
