NS_ERROR_ENUM(kFirebaseInstallationsErrorDomain, FIRInstallationsErrorCode){
    /** Unknown error. See `userInfo` for details. */
    FIRInstallationsErrorCodeUnknown = 0,

    /** Keychain error. See `userInfo` for details. */
    FIRInstallationsErrorCodeKeychain = 1,

    /** Server unreachable. A network error or server is unavailable. See `userInfo` for details. */
    FIRInstallationsErrorCodeServerUnreachable = 2,

    /** FirebaseApp configuration issues e.g. invalid GMP-App-ID, etc. See `userInfo` for details.
     */
    FIRInstallationsErrorCodeInvalidConfiguration = 3,

}