configuring-lazy-prefetch

Create a LazyLayoutCacheWindow with Dp-based ahead and behind values, pass it to rememberLazyListState(cacheWindow = ...), and give that state to LazyColumn. The window is not a parameter on LazyColumn itself, and every call site needs @OptIn(ExperimentalFoundationApi::class).

First ensure items have stable keys, contentType, and skippable composables, then measure with Macrobenchmark FrameTimingMetric. Only widen the prefetch window if the baseline proves prefetch is the bottleneck; on Compose Foundation 1.10+ pausable prefetch is already on by default.

LazyLayoutCacheWindow requires Compose Foundation 1.9 or higher and is an @ExperimentalFoundationApi factory taking ahead and behind Dp values. Pausable composition in prefetch became the default behavior in Compose Foundation 1.10.

Avoid widening when items are cheap and short, when item composables are unstable or non-skippable, or when measure/draw dominates rather than composition. Wide windows increase memory pressure and waste prefetched work on direction reversals without fixing the root cause.

The outer prefetch only warms the row's outer composition, so the inner pager's first page composes on the user's first swipe. Implementing NestedPrefetchScope chains the work so the inner first page composes during the outer prefetch slot.