class_docstr: Basic in-memory dict-based object for saving Task Records.
  
  This is the first object to present the DB interface
  for logging tasks out of memory.
  
  The interface is based on MongoDB, so adding a MongoDB
  backend should be straightforward.
code: def _drop_bytes(self, rec):
      for key in ("buffers", "result_buffers"):
          for buf in rec.get(key) or []:
              self._buffer_bytes -= len(buf)
  
imports: import copy
  from copy import deepcopy
  from datetime import datetime
  from traitlets import Dict, Float, Integer, Unicode
  from traitlets.config.configurable import LoggingConfigurable
  from ..util import ensure_timezone
label_desc: Use image node_id 5 for calling the DictDB obj's underlying member method code with example usage: obj._drop_bytes(rec) without return types