// If empty, it will be defaulted:
  //  1. If it's a kubelet client certificate, it is assigned
  //     "kubernetes.io/kube-apiserver-client-kubelet".
  //  2. If it's a kubelet serving certificate, it is assigned
  //     "kubernetes.io/kubelet-serving".
  //  3. Otherwise, it is assigned "kubernetes.io/legacy-unknown".
  // Distribution of trust for signers happens out of band.
  // You can select on this field using `spec.signerName`.

  // +optional
  optional bool ready = 1;

  // serving is identical to ready except that it is set regardless of the
  // terminating state of endpoints. This condition should be set to true for
  // a ready endpoint that is terminating. If nil, consumers should defer to
  // the ready condition.
  // +optional
  optional bool serving = 2;

  // terminating indicates that this endpoint is terminating. A nil value

message IngressSpec {
  // ingressClassName is the name of an IngressClass cluster resource. Ingress
  // controller implementations use this field to know whether they should be
  // serving this Ingress resource, by a transitive connection
  // (controller -> IngressClass -> Ingress resource). Although the
  // `kubernetes.io/ingress.class` annotation (simple constant name) was never

// MatchCondition represents a condition which must by fulfilled for a request to be sent to a webhook.
message MatchCondition {
  // Name is an identifier for this match condition, used for strategic merging of MatchConditions,
  // as well as providing an identifier for logging purposes. A good name should be descriptive of
  // the associated expression.

  // then this field is set to that version. Otherwise this field is left empty.
  // API servers should finish updating its storageVersionStatus entry before
  // serving write operations, so that this field will be in sync with the reality.
  // +optional
  optional string commonEncodingVersion = 2;

  // The latest available observations of the storageVersion's state.
  // +optional

// MatchCondition represents a condition which must be fulfilled for a request to be sent to a webhook.
message MatchCondition {
  // Name is an identifier for this match condition, used for strategic merging of MatchConditions,
  // as well as providing an identifier for logging purposes. A good name should be descriptive of
  // the associated expression.

  // +optional
  optional bool ready = 1;

  // serving is identical to ready except that it is set regardless of the
  // terminating state of endpoints. This condition should be set to true for
  // a ready endpoint that is terminating. If nil, consumers should defer to
  // the ready condition.
  // +optional
  optional bool serving = 2;

  // terminating indicates that this endpoint is terminating. A nil value

  // +optional
  optional string user = 5;

  // keyring is the path to key ring for RBDUser.
  // Default is /etc/ceph/keyring.
  // More info: https://examples.k8s.io/volumes/rbd/README.md#how-to-use-it
  // +optional
  optional string keyring = 6;

  // secretRef is name of the authentication secret for RBDUser. If provided
  // overrides keyring.
  // Default is nil.

Along with caching, partial computations are a critical performance optimization to ensure that we do not need to build (or send) every resource to every proxy on every change. This is discussed more in the Config Serving section.

### Config Serving

Config serving is the layer that actually accepts proxy clients, connected over bidirectional gRPC streams, and serve them the required configuration.

//
// Kubelets use this API to obtain:
//  1. client certificates to authenticate to kube-apiserver (with the "kubernetes.io/kube-apiserver-client-kubelet" signerName).
//  2. serving certificates for TLS endpoints kube-apiserver can connect to securely (with the "kubernetes.io/kubelet-serving" signerName).
//
// This API can be used to request client certificates to authenticate to kube-apiserver
// (with the "kubernetes.io/kube-apiserver-client" signerName),