code: def flush(self, _async=False, collection_name=None, timeout=None):
      tmp_collection_name = (
          self._collection_name
          if collection_name is None
          else collection_name
      )
      self._milvus.flush(
          [tmp_collection_name], _async=_async, timeout=timeout
      )
  
imports: import random
  import logging
  import time
  from multiprocessing import Process
  from pymilvus import Milvus, DataType
  import utils
  import config
  from milvus_benchmark.runners import utils
label_desc: Use image node_id 15 for calling the MilvusClient obj's underlying member method code with example usage: obj.flush(_async, collection_name, timeout) without return types