class_docstr: Log writer to write vdl records to log file.
  
  The class `LogWriter` provides APIs to create record file and add records to
  it. The class updates log file asynchronously without slowing down training.
class_docstr_tok: ["Log","writer","to","write","vdl","records","to","log","file",".","The","class","`","LogWriter","`","provides","APIs","to","create","record","file","and","add","records","to","it",".","The","class","updates","log","file","asynchronously","without","slowing","down","training","."]
docstr: Add a meta to vdl record file.
  
  Args:
      tag (string): Data identifier
      display_name (string): Display name of `runs`.
      step (int): Step of meta.
      walltime (int): Wall time of scalar
code: def add_meta(
      self, tag="meta_data_tag", display_name="", step=0, walltime=None
  ):
      """Add a meta to vdl record file.
  
      Args:
          tag (string): Data identifier
          display_name (string): Display name of `runs`.
          step (int): Step of meta.
          walltime (int): Wall time of scalar
      """
      if "%" in tag:
          raise RuntimeError("% can't appear in tag!")
      walltime = (
          round(time.time() * 1000) if walltime is None else walltime
      )
      self._get_file_writer().add_record(
          meta_data(
              tag=tag,
              display_name=display_name,
              step=step,
              walltime=walltime,
          )
      )
  
imports: import os
  import time
  import numpy
  from visualdl.component.base_component import audio
  from visualdl.component.base_component import embedding
  from visualdl.component.base_component import histogram
  from visualdl.component.base_component import hparam
  from visualdl.component.base_component import image
  from visualdl.component.base_component import meta_data
  from visualdl.component.base_component import pr_curve
  from visualdl.component.base_component import roc_curve
  from visualdl.component.base_component import scalar
  from visualdl.component.base_component import scalars
  from visualdl.component.base_component import text
  from visualdl.component.graph import translate_graph
  from visualdl.io import bfile
  from visualdl.server.log import logger
  from visualdl.utils.figure_util import figure_to_image
  from visualdl.utils.img_util import merge_images
  from visualdl.utils.md5_util import md5
  from visualdl.writer.record_writer import RecordFileWriter
label_desc: Use image node_id 5 for calling the LogWriter obj's underlying member method code with example usage: obj.add_meta(tag, display_name, step, walltime) without return types