ptrLevel uint
	ptrSeen  map[any]struct{}
}

const startDetectingCyclesAfter = 1000

var encodeStatePool sync.Pool

func newEncodeState() *encodeState {
	if v := encodeStatePool.Get(); v != nil {
		e := v.(*encodeState)
		e.Reset()
		if len(e.ptrSeen) > 0 {
			panic("ptrEncoder.encode should have emptied ptrSeen via defers")
		}
		e.ptrLevel = 0
		return e
	}