anchor.diff:          State;
   maybe_write_blocks(State=#state{free_writers=[]}) ->
           State;
  -maybe_write_blocks(State=#state{buffer_queue=[ToWrite, RestBuffer],
  +maybe_write_blocks(State=#state{buffer_queue=[ToWrite | RestBuffer],
                                   free_writers=FreeWriters,
                                   unacked_writes=UnackedWrites,
                                   bucket=Bucket,
  
positive.code:                 manifest :: lfs_manifest(),
                  content_length :: pos_integer(),
                  content_type :: binary(),
                  num_bytes_received :: non_neg_integer(),
                  max_buffer_size :: non_neg_integer(),
                  current_buffer_size :: non_neg_integer(),
                  buffer_queue=[], %% not actually a queue, but we treat it like one
                  remainder_data :: binary(),
                  free_writers :: ordsets:new(),
                  unacked_writes=ordsets:new(),
                  next_block_id=0,
  
negative.code: done(finalize, _From, State) ->
      %% 1. reply immediately
      %%    with the finished manifest
  
      %% need to synchronously
      %% wait for the manifest
      %% to be saved, I think.
      Reply = ok,
      {reply, Reply, stop, State}.
  
  