Refactor extractHedgeOptions

namespace {

// Only do hedging for commands that cannot trigger writes.

// Keep this list sorted.

static constexpr std::array hedgeCommands{

    "collStats"_sd,

    "count"_sd,

    "dataSize"_sd,

    "dbStats"_sd,

    "distinct"_sd,

    "filemd5"_sd,

    "find"_sd,

    "listCollections"_sd,

    "listIndexes"_sd,

    "planCacheListFilters"_sd,

};

static const bool verifySortOrderOnStartup = [] {

    invariant(std::is_sorted(hedgeCommands.begin(), hedgeCommands.end()));

    return true;

}();

bool commandCanHedge(StringData command) {

    return std::binary_search(hedgeCommands.begin(),

                              hedgeCommands.end(),

                              command);

}

}  // namespace

void extractHedgeOptions(const BSONObj& cmdObj,

                         const ReadPreferenceSetting& readPref,

                         executor::RemoteCommandRequestOnAny::Options& options) {

    const bool canHedge = [&] {

        if (gReadHedgingMode.load() != ReadHedgingMode::kOn)

            return false;  // Hedging is globally disabled.

        auto&& mode = readPref.hedgingMode;

        if (!mode || !mode->getEnabled())

            return false;  // The read preference didn't enable hedging.

        auto cmdName = cmdObj.firstElement().fieldNameStringData();

        if (!commandCanHedge(cmdName))

            return false;  // This is not a command that can hedge.

        return true;

    }();

    options.isHedgeEnabled = canHedge;

    options.hedgeCount = canHedge ? 1 : 0;

    options.maxTimeMSForHedgedReads = canHedge ? gMaxTimeMSForHedgedReads.load() : 0;

}