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.

    singular: gateway
  scope: Namespaced
  versions:
  - name: v1
    schema:
      openAPIV3Schema:
        properties:
          spec:
            description: 'Configuration affecting edge load balancer. See more details
              at: https://istio.io/docs/reference/config/networking/gateway.html'
            properties:
              selector:
                additionalProperties: