When I run `scantxoutset` via RPC using big range (e.g. 10000) on XPUB, the progress report indicator (`scantxoutset status`) reports 100% at start (while the keys are being derived). This is most probably the result of the previous operation. The progress is only reset to zero when the actual scan starts. I would expect the progress is set to zero before the keys are being derived.

Output of periodic calls to `scantxoutset status` while performing long operation.

```
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 0 }
{ progress: 3 }
{ progress: 6 }
{ progress: 9 }
{ progress: 12 }
{ progress: 15 }
{ progress: 17 }
{ progress: 20 }
{ progress: 23 }
{ progress: 26 }
{ progress: 29 }
{ progress: 32 }
{ progress: 35 }
{ progress: 37 }
{ progress: 40 }
{ progress: 43 }
{ progress: 46 }
{ progress: 49 }
{ progress: 51 }
{ progress: 54 }
{ progress: 57 }
{ progress: 60 }
{ progress: 63 }
{ progress: 66 }
{ progress: 68 }
{ progress: 71 }
{ progress: 74 }
{ progress: 77 }
{ progress: 80 }
{ progress: 82 }
{ progress: 85 }
{ progress: 88 }
{ progress: 91 }
{ progress: 94 }
{ progress: 97 }
{ progress: 100 }
```
ret.pushKV("txcount", (int64_t)pindex->nChainTx);
    ret.pushKV("window_final_block_hash", pindex->GetBlockHash().GetHex());
    ret.pushKV("window_final_block_height", pindex->nHeight);
    ret.pushKV("window_block_count", blockcount);
    if (blockcount > 0) {
        ret.pushKV("window_tx_count", nTxDiff);
        ret.pushKV("window_interval", nTimeDiff);
        if (nTimeDiff > 0) {
            ret.pushKV("txrate", ((double)nTxDiff) / nTimeDiff);
        }
    }
    return ret;
},
    };
}
template<typename T>
static T CalculateTruncatedMedian(std::vector<T>& scores)
{
    size_t size = scores.size();
    if (size == 0) {
        return 0;
    }
    std::sort(scores.begin(), scores.end());
    if (size % 2 == 0) {
        return (scores[size / 2 - 1] + scores[size / 2]) / 2;
    } else {
        return scores[size / 2];
    }
}
void CalculatePercentilesByWeight(CAmount result[NUM_GETBLOCKSTATS_PERCENTILES], std::vector<std::pair<CAmount, int64_t>>& scores, int64_t total_weight)