## 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.

	// The idea is to do the compile with a trace option turned
	// on and then pick up on the frame offsets of specific
	// variables.
	//
	// Stack slot merging is a greedy algorithm, and there can
	// be many possible ways to overlap a given set of candidate
	// variables, all of them legal. Rather than locking down
	// a specific set of overlappings or frame offsets, this
	// tests just verifies that there is a decent-sized clump of 4+ vars that

|SKIPPED
|Task was explicitly prevented from running

|FROM-CACHE
|Task output has been copied to local directory from previous builds in the build cache (caching feature)

|NO-SOURCE
|Task was not executed because its required inputs were not available
|===

If there is no label, the task was newly executed by Gradle (locally).

	}

	// TODO: it is needlessly wasteful to do a full sync just because the rest of Istio thought it was "full"
	// The rest of Istio xDS types would treat `req.Full && len(req.ConfigsUpdated) == 0` as a need to trigger a "full" push.
	// This is only an escape hatch for a lack of complete mapping of "Input changed -> Output changed".
	// WDS does not suffer this limitation, so we could almost safely ignore these.

Have a look at the table below to understand the meaning of the different terms used:

.Terminology
[%header%autowidth,compact]
|===
| Reason    | Meaning

| (Absent)
| No reason other than a reference, direct or transitive, was present.

| Was requested : <text>

// response returned the optimal result. Checks include correctness checks (e.g. if a config changed,
// we must include it) and possible optimizations (e.g. we sent a config, but it was not changed).
func (s *DiscoveryServer) compareDiff(
	con *Connection,
	w *model.WatchedResource,
	sotwRes model.Resources,
	deltaRes model.Resources,
	deleted model.DeletedResources,
	usedDelta bool,

But you should first read the **Tutorial - User Guide** (what you are reading right now).

    * `Path()`
    * `Query()`
    * `Header()`
    * `Cookie()`
* <a href="https://github.com/OAI/OpenAPI-Specification/blob/main/versions/3.1.0.md#media-type-object" class="external-link" target="_blank">`Request Body Object`, in the field `content`, on the `Media Type Object` (in the specification)</a> that was used by FastAPI's:
    * `Body()`
    * `File()`

		setupMake.Do(registerCleanup)
		ma = addUniqueMap[T](typ)
	}
	m := ma.(*uniqueMap[T])

	// Keep around any values we allocate for insertion. There
	// are a few different ways we can race with other threads
	// and create values that we might discard. By keeping
	// the first one we make around, we can avoid generating
	// more than one per racing thread.
	var (

		// even though Nonce match and it looks like an ACK.
		if alwaysRespond {
			deltaLog.Infof("ADS:%s: FORCE RESPONSE %s for warming.", stype, con.ID())
			return true
		}

		deltaLog.Debugf("ADS:%s: ACK %s %s", stype, con.ID(), request.ResponseNonce)
		return false
	}
	deltaLog.Debugf("ADS:%s: RESOURCE CHANGE previous resources: %v, new resources: %v %s %s", stype,