return func(t *testing.T, pageSize, estimatedProcessedObjects uint64) {
		if reads := transformer.GetReadsAndReset(); reads != estimatedProcessedObjects {
			t.Errorf("unexpected reads: %d, expected: %d", reads, estimatedProcessedObjects)
		}
		estimatedGetCalls := uint64(1)
		if pageSize != 0 {

	if dataCtx == nil {
		panic("no context provided")
	}
	if len(data) > 0 {
		return append(append([]byte{}, p.prefix...), data...), p.err
	}
	return data, p.err
}

func (p *PrefixTransformer) GetReadsAndReset() uint64 {
	return atomic.SwapUint64(&p.reads, 0)
}

// reproducingTransformer is a custom test-only transformer used purely
// for testing consistency.