class_docstr: Metric object.
class_docstr_tok: ["Metric","object","."]
code: def to_proto(self):
      metric = ProtoMetric()
      metric.key = self.key
      metric.value = self.value
      metric.timestamp = self.timestamp
      metric.step = self.step
      return metric
  
file_path: mlflow/mlflow/entities/metric.py
imports: from mlflow.entities._mlflow_object import _MLflowObject
  from mlflow.protos.service_pb2 import Metric
label_desc: Use image node_id 6 for calling the Metric obj's underlying member method code with example usage: obj.to_proto() and returns: metric