//   matches /foo/bar/baz, but does not match /foo/barbaz).
  // * ImplementationSpecific: Interpretation of the Path matching is up to
  //   the IngressClass. Implementations can treat this as a separate PathType
  //   or treat it identically to Prefix or Exact path types.
  // Implementations are required to support all path types.
  // Defaults to ImplementationSpecific.
  optional string pathType = 3;

  //   matches /foo/bar/baz, but does not match /foo/barbaz).
  // * ImplementationSpecific: Interpretation of the Path matching is up to
  //   the IngressClass. Implementations can treat this as a separate PathType
  //   or treat it identically to Prefix or Exact path types.
  // Implementations are required to support all path types.
  optional string pathType = 3;

  // backend defines the referenced service endpoint to which the traffic

## Proxy implementation

In its initial implementations, the ztunnel was actually implemented in 3 different ways: a bespoke Rust implementation, a bespoke Go implementation, and in Envoy.

In the end, [after evaluation](https://docs.google.com/document/d/1c2123cKuYsBDpIon9FFdctWTUIMFweSjgwG7r8l3818/edit), the decision was to move forward with a Rust implementation.

  // validity duration so a client must check the delta between the notBefore and
  // and notAfter fields in the issued certificate to determine the actual duration.
  //
  // The v1.22+ in-tree implementations of the well-known Kubernetes signers will
  // honor this field as long as the requested duration is not greater than the
  // maximum duration they will honor per the --cluster-signing-duration CLI

* The Gateway Class controller is a simple controller that just writes a default `GatewayClass` object describing our implementation.

  //   matches /foo/bar/baz, but does not match /foo/barbaz).
  // * ImplementationSpecific: Interpretation of the Path matching is up to
  //   the IngressClass. Implementations can treat this as a separate PathType
  //   or treat it identically to Prefix or Exact path types.
  // Implementations are required to support all path types.
  // Defaults to ImplementationSpecific.
  optional string pathType = 3;

| HOST_PROBE_SNAT_IPV6 | "fd16:9254:7127:1337:ffff:ffff:ffff:ffff" | IPv6 link local ranges are designed to be collision-resistant by default, and so this probably never needs to be overridden |

## Sidecar Mode Implementation Details

Istio CNI injection is currently based on the same Pod annotations used in init-container/inject mode.

### Selection API

- plugin config "exclude namespaces" applies first
- ambient is enabled if:

  // +optional
  optional k8s.io.apimachinery.pkg.util.intstr.IntOrString maxUnavailable = 3;

  // UnhealthyPodEvictionPolicy defines the criteria for when unhealthy pods
  // should be considered for eviction. Current implementation considers healthy pods,
  // as pods that have status.conditions item with type="Ready",status="True".
  //
  // Valid policies are IfHealthyBudget and AlwaysAllow.