code: def testInflightClosures(self):
      self.coordinator.schedule(long_function)
      self.coordinator.schedule(long_function)
      self.assertGreater(
          metric_utils.get_metric_summary("queued_closures"), 0
      )
  
      # inflight closures should be greater than 0 at some point
      max_inflight = 0
      while not self.coordinator.done():
          with self.coordinator._cluster.closure_queue._queue_lock:
              inflight_metric = metric_utils.get_metric_summary(
                  "inflight_closures"
              )
          max_inflight = max(max_inflight, inflight_metric)
          time.sleep(0.01)
      self.assertGreater(max_inflight, 0)
  
imports: import time
  from tensorflow.python.distribute import multi_process_runner
  from tensorflow.python.distribute import multi_worker_test_base
  from tensorflow.python.distribute import parameter_server_strategy_v2
  from tensorflow.python.distribute.cluster_resolver import cluster_resolver
  from tensorflow.python.distribute.coordinator import cluster_coordinator
  from tensorflow.python.distribute.coordinator import metric_utils
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  from tensorflow.python.eager import test
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import random_ops
  from tensorflow.python.training import coordinator
  from tensorflow.python.training.server_lib import ClusterSpec
label_desc: Use image node_id 6 for calling the MetricUtilsTest obj's underlying member method code with example usage: obj.testInflightClosures() without return types