class_docstr: An obscure object encompassing timing results recorded by
  :func:`~cupyx.profiler.benchmark`. Simple statistics can be obtained by
  converting an instance of this class to a string.
  
  .. warning::
      This API is currently experimental and subject to change in future
      releases.
code: def _to_str_per_item(device_name, t):
      assert t.ndim == 1
      assert t.size > 0
      t_us = t * 1e6
  
      s = "    {}: {:9.03f} us".format(device_name, t_us.mean())
      if t.size > 1:
          s += "   +/- {:6.03f} (min: {:9.03f} / max: {:9.03f}) us".format(
              t_us.std(), t_us.min(), t_us.max()
          )
      return s
  
file_path: cupy/cupyx/profiler/_time.py
imports: import math
  import time
  import numpy
  import cupy
  from cupy_backends.cuda.api import runtime
label_desc: Use image node_id 5 for calling the _PerfCaseResult obj's underlying member method code with example usage: obj._to_str_per_item(device_name, t) and returns: s