code: def _build_trial_meta(cls, expr_dir):
          
          meta_file = os.path.join(expr_dir, EXPR_META_FILE)
          meta = parse_json(meta_file)
  
          if not meta:
              job_id = expr_dir.split("/")[-2]
              trial_id = expr_dir[-8:]
              params = parse_json(os.path.join(expr_dir, EXPR_PARARM_FILE))
              meta = {
                  "trial_id": trial_id,
                  "job_id": job_id,
                  "status": "RUNNING",
                  "type": "TUNE",
                  "start_time": os.path.getctime(expr_dir),
                  "end_time": None,
                  "progress_offset": 0,
                  "result_offset": 0,
                  "params": params
              }
  
          if not meta.get("start_time", None):
              meta["start_time"] = os.path.getctime(expr_dir)
  
          if isinstance(meta["start_time"], float):
              meta["start_time"] = timestamp2date(meta["start_time"])
  
          if meta.get("end_time", None):
              meta["end_time"] = timestamp2date(meta["end_time"])
  
          meta["params"] = parse_json(os.path.join(expr_dir, EXPR_PARARM_FILE))
  
          return meta
docs: Build meta file for trial.
  
          Args:
              expr_dir (str): Directory path of the experiment.
  
          Return:
              A dict of trial meta info.