Why queue two frame at most instread of read the latest frame?

[junlinp]

alvr-visionos/ALVRClient/Renderer.swift

Line 598 in 6005e8c

queuedFrame = EventHandler.shared.frameQueue.count > 0 ? EventHandler.shared.frameQueue.removeFirst() : nil

should it read the latest one frame in the queue?
two frame cache would cause 22 ms around latency when the render rate is 90Hz.

[shinyquagsire23]

stability reasons mostly, the buffer allows small circumstantial frame drops to be less noticable and large frame drops to be used as an opportunity to fill the buffer