docs: public static void checkpoint(NetworkParameters params, InputStream checkpoints, BlockStore store, long time)
              throws IOException, BlockStoreException {
          checkNotNull(params);
          checkNotNull(store);
          checkArgument(!(store instanceof FullPrunedBlockStore), "You cannot use checkpointing with a full store.");
  
          time -= 86400 * 7;
  
          checkArgument(time > 0);
          log.info("Attempting to initialize a new block store with a checkpoint for time {} ({})", time, Utils.dateTimeFormat(time * 1000));
  
          BufferedInputStream stream = new BufferedInputStream(checkpoints);
          CheckpointManager manager = new CheckpointManager(params, stream);
          StoredBlock checkpoint = manager.getCheckpointBefore(time);
          store.put(checkpoint);
          store.setChainHead(checkpoint);
      }