why does UnityWebRequest want Dispose() ?

The [Unity Docs][1] state:> Signals that this [UnityWebRequest] is no longer being used, and should clean up any resources it is using.>> You must call Dispose once you have finished using a [UnityWebRequest] object, regardless of whether the request succeeded or failed. Why doesn't UnityWebRequest rely on regular garbage collection ? [1]: https://docs.unity3d.com/ScriptReference/Networking.UnityWebRequest.Dispose.html