class_docstr: Write records in the following format for a single record event_str:
  uint64 len(event_str)
  uint32 masked crc of len(event_str)
  byte event_str
  uint32 masked crc of event_str
  The implementation is ported from
  https://github.com/tensorflow/tensorflow/blob/master/tensorflow/core/lib/io/record_writer.cc
  Here we simply define a byte string _dest to buffer the record to be written to files.
  The flush and close mechanism is totally controlled in this class.
  In TensorFlow, _dest is a object instance of ZlibOutputBuffer (C++) which has its own flush
  and close mechanism defined.
code: def __del__(self):
      self.close()
  
file_path: mxboard/python/mxboard/record_writer.py
imports: from __future__ import absolute_import
  import struct
  from ._crc32c import crc32c
label_desc: Use image node_id 2 for calling the RecordWriter obj's underlying member method code with example usage: obj.__del__() without return types