Instead, an Istio specific field like `ExpectedTLSIdentity: spiffe://foo.bar` can encode the same information, at a fraction of the cost.

In our testing, even the most generous representations give custom types a 10x edge (in size, allocations, and CPU time) over Envoy types.
In addition, they are more clear and strictly typed; using Envoy types would require us to put a lot of information in untyped `metadata` maps.

// the Data field. ControllerRevisions may, however, be deleted. Note that, due to its use by both
// the DaemonSet and StatefulSet controllers for update and rollback, this object is beta. However,
// it may be subject to name and representation changes in future releases, and clients should not
// depend on its stability. It is primarily for internal use by controllers.
message ControllerRevision {
  // Standard object's metadata.

     distribute the Covered Software under a subsequent version of this
     License (see Section 10.2) or under the terms of a Secondary License (if
     permitted under the terms of Section 3.3).

2.5. Representation

     Each Contributor represents that the Contributor believes its
     Contributions are its original creation(s) or it has sufficient rights to
     grant the rights to its Contributions conveyed by this License.

// the Data field. ControllerRevisions may, however, be deleted. Note that, due to its use by both
// the DaemonSet and StatefulSet controllers for update and rollback, this object is beta. However,
// it may be subject to name and representation changes in future releases, and clients should not
// depend on its stability. It is primarily for internal use by controllers.
message ControllerRevision {
  // Standard object's metadata.

`Generators` get as input the `Proxy` (a representation of the current client), the current `PushContext` snapshot, and a list of config updates that caused the change.

// the Data field. ControllerRevisions may, however, be deleted. Note that, due to its use by both
// the DaemonSet and StatefulSet controllers for update and rollback, this object is beta. However,
// it may be subject to name and representation changes in future releases, and clients should not
// depend on its stability. It is primarily for internal use by controllers.
message ControllerRevision {
  // Standard object's metadata.