code: @Override
      public boolean allPresent(String id) {
          if (!chunks.containsKey(id))
              return false;
          List<NDArrayMessageChunk> chunkList = chunks.get(id);
          return chunkList.size() == chunkList.get(0).getNumChunks();
      }
docs: Returns true if all chunks are present
  
  @param id the id to check for
  @return true if all the chunks are present,false otherwise