message: Let _replace() return a copy of object instead of changing the object
  The idea is to make DEFAULT_TRT_CONVERSION_PARAMS immutable.
  Although this doesn't make it completely immutable but it avoids
  changing the object by _replace(), which is the method everyone is
  using on DEFAULT_TRT_CONVERSION_PARAMS when it was a NamedTuple.
diff: @@ -192,10 +192,11 @@ class TrtConversionParams(object):
  set parameters:
  DEFAULT_TRT_CONVERSION_PARAMS._replace(...)
  """
  + trt_conversion_params = TrtConversionParams()
  for k, v in vars().items():
  if v and (k != "self"):
  - setattr(self, k, v)
  - return self
  + setattr(trt_conversion_params, k, v)
  + return trt_conversion_params
  DEFAULT_TRT_CONVERSION_PARAMS = TrtConversionParams()
  