message: Impl Freeze for FrozenRef
  Summary: Used later.
diff: @@ -28,6 +28,8 @@ use std::sync::atomic;
  use gazebo::prelude::*;
  +use crate::values::Freeze;
  +use crate::values::Freezer;
  use crate::values::Trace;
  use crate::values::Tracer;
  @@ -138,6 +140,14 @@ where
  }
  }
  +impl<'f, T: 'f + ?Sized> Freeze for FrozenRef<'f, T> {
  + type Frozen = Self;
  +
  + fn freeze(self, _freezer: &Freezer) -> anyhow::Result<Self::Frozen> {
  + Ok(self)
  + }
  +}
  +
  /// `Atomic<Option<FrozenRef<T>>>`.
  pub(crate) struct AtomicFrozenRefOption<T>(atomic::AtomicPtr<T>);
  