The MIT License (MIT)

Copyright (c) 2014 Brian Goff

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is

## Features requiring API changes

If a PR change requires an API change
* Updates to documentation do not require explicit approval from the Technical Oversight Committee (TOC). This can be
  held off after the release. Hiding/Showing documentation does not require TOC approval.
* Cases for other API changes require TOC approval

    CZ--"HBONE (actual)"-->SZ
    SZ--Plain-->Server
```

### Pooling

User connections can be multiplexed over shared HBONE connections.
This is done through standard HTTP/2 pooling.
The pooling is keyed off the `{source identity, destination identity, destination ip}`.

### Headers

Ztunnel uses the following well-known headers in HBONE:

defines install time parameters like component and enablement and namespace, and K8s settings like resources, HPA spec etc. in a structured way.
The simplest customization is to turn components on and off. For example, to turn on cni ([samples/cni-on.yaml](samples/cni-on.yaml):

```yaml
apiVersion: install.istio.io/v1alpha1
kind: IstioOperator
spec:
  components:
    cni:
      enabled: true
```

not impact the `Cluster` type, so we can skip generating `Cluster` in this case. Warning: Envoy currently has a bug that *requires* `Endpoints` to be pushed any time the corresponding `Cluster` is pushed, so this optimization is intentionally turned off in this specific case.

Finally, we determine which subset of the type we need to generate. XDS has two modes - "State of the World (SotW)" and "Delta". In SotW, we generally need to generate all resources of the type, even if only one changed....