The new `getrpcinfo` shows a list of the active commands and the duration each command has been running. This sounds like a good place to report a completion percentage for any command doing a blockchain rescan, to solve [this problem](https://bitcoin.stackexchange.com/q/83236/90721).
std::vector<OutputGroup> GroupOutputs(const std::vector<COutput>& outputs, bool single_coin) const;
    bool IsLockedCoin(uint256 hash, unsigned int n) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void LockCoin(const COutPoint& output) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void UnlockCoin(const COutPoint& output) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void UnlockAllCoins() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void ListLockedCoins(std::vector<COutPoint>& vOutpts) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    /*
     * Rescan abort properties
     */
    void AbortRescan() { fAbortRescan = true; }
    bool IsAbortingRescan() { return fAbortRescan; }
    bool IsScanning() { return fScanningWallet; }
    int64_t ScanningDuration() const { return fScanningWallet ? GetTimeMillis() - m_scanning_start : 0; }
    double ScanningProgress() const { return fScanningWallet ? (double) m_scanning_progress : 0; }
    /**
     * keystore implementation
     * Generate a new key
     */
    CPubKey GenerateNewKey(WalletBatch& batch, bool internal = false) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    
    bool AddKeyPubKey(const CKey& key, const CPubKey &pubkey) override EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    bool AddKeyPubKeyWithDB(WalletBatch &batch,const CKey& key, const CPubKey &pubkey) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    
    bool LoadKey(const CKey& key, const CPubKey &pubkey) { return CCryptoKeyStore::AddKeyPubKey(key, pubkey); }
    
    void LoadKeyMetadata(const CKeyID& keyID, const CKeyMetadata &metadata) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void LoadScriptMetadata(const CScriptID& script_id, const CKeyMetadata &metadata) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    
    void UpgradeKeyMetadata() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    bool LoadMinVersion(int nVersion) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) { AssertLockHeld(cs_wallet); nWalletVersion = nVersion; nWalletMaxVersion = std::max(nWalletMaxVersion, nVersion); return true; }