class_docstr: CheckIn is a dataclass that represents a single check-in.
  
  All the time-related fields are in `time.monotonic`, relative time expressed in
  seconds, until stated otherwise. In case of `expect_next_in=0` we treat it as
  a special case, meaning that the check-in is not expected to expire.
  Indicies are used to identify check-ins and are unique within a run, auto-incremented.
docstr: Physically write the check-in to the filesystem so that it is visible to the
  other nodes that share the filesystem.
  
  As `CheckIn.touch()` could be called much later that it is created, we
  need to calibrate `expected_next_in` w.r.t. current time. If `calibrate` is
  `False` (`True` by default), then `expected_next_in` is not recalibrated.
  
  If `cleanup` is True (default), this will remove all the expired check-ins.
docstr_tok: ["Physically","write","the","check-in","to","the","filesystem","so","that","it","is","visible","to","the","other","nodes","that","share","the","filesystem",".","As","`","CheckIn.touch","(",")","`","could","be","called","much","later","that","it","is","created",",","we","need","to","calibrate","`","expected_next_in","`","w.r.t",".","current","time",".","If","`","calibrate","`","is","`","False","`","(","`","True","`","by","default",")",",","then","`","expected_next_in","`","is","not","recalibrated",".","If","`","cleanup","`","is","True","(","default",")",",","this","will","remove","all","the","expired","check-ins","."]
code: def touch(
      self,
      *,
      file_mgr,
      run_hash: str,
      cleanup: bool = True,
      calibrate: bool = True,
  ) -> "CheckIn":
      """
      Physically write the check-in to the filesystem so that it is visible to the
      other nodes that share the filesystem.
  
      As `CheckIn.touch()` could be called much later that it is created, we
      need to calibrate `expected_next_in` w.r.t. current time. If `calibrate` is
      `False` (`True` by default), then `expected_next_in` is not recalibrated.
  
      If `cleanup` is True (default), this will remove all the expired check-ins.
      """
  
      if calibrate and self.expect_next_in:
          return self.time_calibrated().touch(
              file_mgr=file_mgr,
              run_hash=run_hash,
              cleanup=cleanup,
              calibrate=False,
          )
  
      utc_time = time.time()
      filename = self.generate_filename(
          run_hash=run_hash,
          idx=self.idx,
          expect_next_in=self.expect_next_in,
          absolute_time=utc_time,
          flag_name=self.flag_name,
      )
  
      cleanup_file_pattern = (
          self.generate_filename(
              run_hash=run_hash, flag_name=self.flag_name
          )
          if cleanup
          else None
      )
  
      file_mgr.touch(filename, cleanup_file_pattern)
  
      return self
  
imports: import math
  import time
  import queue
  import threading
  from collections import defaultdict
  from dataclasses import dataclass, field
  from pathlib import Path
  from typing import ClassVar, Dict, Optional, Tuple, Set, Union, TYPE_CHECKING
  from cachetools import LRUCache
  from aim.sdk.reporter.file_manager import FileManager
  import logging
label_desc: Use image node_id 8 for calling the CheckIn obj's underlying member method code with example usage: obj.touch() and returns: self, self