Let's comment this since as you pointed out its a bit different than `api` Canonicalize methods. Maybe something like:  ```suggestion  // Canonicalize Allocation to ensure fields are initialized to the expectations  // of this version of Nomad. Should be called when restoring persisted  // Allocations or receiving Allocations from Nomad agents potentially on an  // older version of Nomad.  func (a *Allocation) Canonicalize() {  ```