class_docstr: The Epoch Max GPU metric.
  This plugin metric only works at training time.
class_docstr_tok: ["The","Epoch","Max","GPU","metric",".","This","plugin","metric","only","works","at","training","time","."]
code: def before_training(self, strategy: "SupervisedTemplate"):
      super().before_training(strategy)
      self._metric.start_thread()
  
imports: import GPUtil
  from threading import Thread
  import time
  import warnings
  from typing import Optional, TYPE_CHECKING, List
  from avalanche.evaluation import Metric, PluginMetric, GenericPluginMetric
  from avalanche.evaluation.metric_results import MetricResult
label_desc: Use image node_id 2 for calling the EpochMaxGPU obj's underlying member method code with example usage: obj.before_training(strategy) without return types