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kotlinlang

You can do `unfilteredResultsCache.filterNot { it.value.timeStamp.toEpochSecond(offset) &lt; lastHourEpoch }`, which will only create 1 new collection. Not one collection for every element removed.

ok so something like this would be more safe

private fun sweepOldResults(){
        val offset = OffsetDateTime.now().offset
        val lastHourEpoch = LocalDateTime.now().minusHours(1).toEpochSecond(offset)

        val iter = unfilteredResultsCache.iterator()
        iter.forEach {
            if(it.value.timeStamp.toEpochSecond(offset) &lt; lastHourEpoch)
                iter.remove()
        }
    }