class_docstr: Metric to track an arbitrary counter.
  
  This is useful for, e.g., tracking the current train/eval iteration number.
  
  To increment the counter, you can __call__ it (e.g. metric_obj()).
code: def reset(self):
      self._np_state.count = np.int64(0)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import abc
  from typing import Any, Iterable, Optional, Text
  import gin
  import numpy
  import six
  from tf_agents.metrics import py_metric
  from tf_agents.trajectories import trajectory
  from tf_agents.typing import types
  from tf_agents.utils import nest_utils
  from tf_agents.utils import numpy_storage
label_desc: Use image node_id 2 for calling the CounterMetric obj's underlying member method code with example usage: obj.reset() without return types