getAria2cPath = (_platform, _arch) => {
        if (_arch == "x32") {
            _arch = "ia32"
        }

        const aria2Dir = path.join(__dirname, "aria2")
        const p = path.join(aria2Dir, _platform, _arch, aria2c_bin)

        if (!fs.existsSync(p)) {
            // find existed aria2c
            const _platform = findFirstSubdirName(aria2Dir)
            const platformDir = path.join(aria2Dir, _platform)
            const _arch = findFirstSubdirName(platformDir)
            return path.join(platformDir, _arch, aria2c_bin)
        } else {
            return p
        }
    }
@param {NodeJS.Platform} _platform
@param {"arm"| "arm64"| "ia32"| "mips"| "mipsel"| "ppc"| "ppc64"| "s390"| "s390x"| "x32"| "x64" | string} _arch
@returns {string}