This object counts how many times this specific association's local receive window actually reached zero bytes. A nonzero count means the local device told that peer to stop sending entirely at least once; the peer would have paused transmission until the window reopened, adding latency to whatever signaling was queued at that moment. This counter incrementing during a CPU-load spike on the device would explain a brief pause in inbound signaling processing that coincided with high local resource contention.