message: Allocative for FrozenRef
  Summary: Needed for the following diff
diff: @@ -26,6 +26,7 @@ use std::ops::Deref;
  use std::ptr;
  use std::sync::atomic;
  +use allocative::Allocative;
  use gazebo::prelude::*;
  use crate::values::Freeze;
  @@ -38,7 +39,8 @@ use crate::values::Tracer;
  /// However, this keeps the type of the type `T` of the actual
  /// [`FrozenValue`](crate::values::FrozenValue) as a
  /// reference, allowing manipulation of the actual typed data.
  -#[derive(Clone_, Dupe_, Copy_, Debug)]
  +#[derive(Clone_, Dupe_, Copy_, Debug, Allocative)]
  +#[allocative(bound = "", skip)] // Data is owned by heap.
  pub struct FrozenRef<'f, T: 'f + ?Sized> {
  pub(crate) value: &'f T,
  }
  