class_docstr: A Branin ``BackendSimulatorTimestampMapMetric`` with a multiplicative
  factor of ``1 - exp(-rate * t)`` where ``t`` is the runtime of the trial.
docstr: Given a starting and current time, get the list of intermediate
  timestamps at which we have observations.
code: def convert_to_timestamps(
      self, start_time: Optional[float], end_time: float
  ) -> List[float]:
      """Given a starting and current time, get the list of intermediate
      timestamps at which we have observations."""
      if start_time is None:
          # NOTE: This can be the case for trials on backend simulator
          # that are queued.
          return []
      num_periods_running = (end_time - start_time) // self.delta_t
      return list(np.arange(num_periods_running) * self.delta_t)
  
file_path: Ax/ax/utils/testing/metrics/branin_backend_map.py
imports: from typing import List, Optional
  import numpy
  from ax.metrics.branin_map import BraninTimestampMapMetric
  from ax.utils.testing.metrics.backend_simulator_map import BackendSimulatorTimestampMapMetric
label_desc: Use image node_id 2 for calling the BraninBackendMapMetric obj's underlying member method code with example usage: obj.convert_to_timestamps(start_time, end_time) and returns: list, list