// are specific to the node & CRI configuration.  It is assumed that all
  // handlers are available on every node, and handlers of the same name are
  // equivalent on every node.
  // For example, a handler called "runc" might specify that the runc OCI
  // runtime (using native Linux containers) will be used to run the containers
  // in a pod.
  // The handler must be lowercase, conform to the DNS Label (RFC 1123) requirements,
  // and is immutable.

  // e.g. `meta.k8s.io/v1.DeleteOptions` or `meta.k8s.io/v1.CreateOptions`. This may be
  // different than the options the caller provided. e.g. for a patch request the performed
  // Operation might be a CREATE, in which case the Options will a
  // `meta.k8s.io/v1.CreateOptions` even though the caller provided `meta.k8s.io/v1.PatchOptions`.
  // +optional
  optional k8s.io.apimachinery.pkg.runtime.RawExtension options = 12;

  // but not yet healthy are considered disrupted and can be evicted regardless
  // of whether the criteria in a PDB is met. This means perspective running
  // pods of a disrupted application might not get a chance to become healthy.
  // Healthy pods will be subject to the PDB for eviction.
  //
  // Additional policies may be added in the future.

  // are specific to the node & CRI configuration.  It is assumed that all
  // handlers are available on every node, and handlers of the same name are
  // equivalent on every node.
  // For example, a handler called "runc" might specify that the runc OCI
  // runtime (using native Linux containers) will be used to run the containers
  // in a pod.
  // The Handler must be lowercase, conform to the DNS Label (RFC 1123) requirements,
  // and is immutable.

  // values are specific to the node & CRI configuration.  It is assumed that
  // all handlers are available on every node, and handlers of the same name are
  // equivalent on every node.
  // For example, a handler called "runc" might specify that the runc OCI
  // runtime (using native Linux containers) will be used to run the containers
  // in a pod.
  // The runtimeHandler must be lowercase, conform to the DNS Label (RFC 1123)

  // items is the list of VolumeAttachments
  repeated VolumeAttachment items = 2;
}

// VolumeAttachmentSource represents a volume that should be attached.
// Right now only PersistenVolumes can be attached via external attacher,
// in future we may allow also inline volumes in pods.
// Exactly one member can be set.
message VolumeAttachmentSource {

  // e.g. `meta.k8s.io/v1.DeleteOptions` or `meta.k8s.io/v1.CreateOptions`. This may be
  // different than the options the caller provided. e.g. for a patch request the performed
  // Operation might be a CREATE, in which case the Options will a
  // `meta.k8s.io/v1.CreateOptions` even though the caller provided `meta.k8s.io/v1.PatchOptions`.
  // +optional
  optional k8s.io.apimachinery.pkg.runtime.RawExtension options = 12;

    ic["Istio kube.Client"]
    ikc["Istio kclient.Client"]
    ikrt["Istio krt.Collection"]
    ikrt--"Builds on"-->ikc--"Builds on"-->ic--"Builds on"-->kcg
```

**`kube.Client`** is a fairly light wrapper around Kubernetes clients, but offers quite a few benefits.
Istio consumes _many_ different types of clients (at the time of writing, 7), as well as informers for each of these.