Clarification on one of the fuction in TargetMover.cs example code

#1

Firstly forgive me if this is too obvious and my basic unity/c# fundamentals seem lacking but I want to understand why there is a while(true) in this function in TargetMover.cs example code:

IEnumerator OptimizeFormationDestinations (List<IAstarAI> ais, List<Vector3> destinations) {

			var alreadySwapped = new HashSet<(IAstarAI, IAstarAI)>();

			const int IterationsPerFrame = 4;
                        
                         // This guy over here what I don't understand 
			while (true) {
				for (int i = 0; i < IterationsPerFrame; i++) {
					var a = Random.Range(0, ais.Count);
					var b = Random.Range(0, ais.Count);
					if (a == b) continue;
					if (b < a) Memory.Swap(ref a, ref b);
					var aiA = ais[a];
					var aiB = ais[b];

					if ((MonoBehaviour)aiA == null) continue;
					if ((MonoBehaviour)aiB == null) continue;

					if (alreadySwapped.Contains((aiA, aiB))) continue;

					var pA = aiA.position;
					var pB = aiB.position;
					var distA = (pA - destinations[a]).sqrMagnitude;
					var distB = (pB - destinations[b]).sqrMagnitude;

					var newDistA = (pA - destinations[b]).sqrMagnitude;
					var newDistB = (pB - destinations[a]).sqrMagnitude;
					var cost1 = distA + distB;
					var cost2 = newDistA + newDistB;
					if (cost2 < cost1 * 0.98f) {
						// Swap the destinations
						var tmp = destinations[a];
						destinations[a] = destinations[b];
						destinations[b] = tmp;

						aiA.destination = destinations[a];
						aiB.destination = destinations[b];

						alreadySwapped.Add((aiA, aiB));
					}
				}
				yield return null; // this is reach after the 4 iterations of the for loop and would immendiately break the while loop? if that the case why have the while loop
			}
		}

also would setting aiA.destination to some destination automatically start the the agent with followerEntity to move to that destination until given a new path or he reaches there?

#2

It is used to run the inner loop every frame. Note the yield return null statement. When using unity coroutines this essentially means “wait one frame”.