message: This change adds an attribute to the _HostCast op to have the same interface as the Cast op.
diff: @@ -122,6 +122,7 @@ REGISTER_OP("_HostCast")
  .Output("y: DstT")
  .Attr("SrcT: type")
  .Attr("DstT: type")
  + .Attr("Truncate: bool = false")
  .SetShapeFn(shape_inference::UnchangedShape)
  .Doc(R"doc(
  Cast x of type SrcT to y of DstT.
  