我已经使用gmail api下载了附件，其格式如下所示。
格式----＆GT; JVBERi0xLjQKMSAwIG9iago8PAovVGl0bGUgKP7_AGkATwBTACAAJgAgAE8AYgBqAGUAYwB0AGkAdgBlAC0AQwAgAFIAZQBwAG8AcgB0KQovQ3JlYXRvciAo_v8pCi9Qcm9kdWNlciAo_v8AdwBrAGgAdABtAGwAdABvAHAAZABmKQovQ3JlYXRpb25EYXRlIChEOjIwMTcwNTEyMDMyODU4LTA0JzAwJykKPj4KZW5kb2JqCjMgMCBvYmoKPDwKL1R5cGUgL0V4dEdTdGF0ZQovU0EgdHJ1ZQovU00gMC4wMgovY2EgMS4wCi9DQSAxLjAKL0FJUyBmYWxzZQovU01hc2sgL05vbmU-PBu4r_AK4NIiSnFYpcMAV6XNeRN1bjMD1NUT5VdhH_ACJNZ48dsjhHnky1xqbER1H2ltqHdL9is246t4sOK0tNnVemQYwmLYvK27LcdUANQJFFNlQl_FC31tIkSbmHN9eYp01irVqWwjz4R5EgSYaYaROAAwGwoPyiJuu1ivWiTu2vBKTUy0tdtUSfi3GrPXGti8nSOXWb5pE_IF81mHQaBQLfrTMyMsGQDwSxcZjkQNR20RsQFF2FE22-NdfjcrHWPxfZVNttbrpHn1OLyuJktP5rvs1VJPZ9ZXh0JsgUOTBC5HoNZiUC2bQuV2DQqu8r5vpObFBcaYRoTJBPihlyT9P-uupg5lb9tbUd75KTZKI7fFzGq6I5PI4Vsffet1SmPJFbOZ7vBRLh9WWXses3hWSekVyNCeoz0cHKdV4brZg46i8TQEFd-JfOxCiivRdfMfK8bi4ElidldPWrT0X7-jh9T6v4jlczO28yq6NaWTWr36beqTXQ22t3BQbahJUrjrcCgU5XBZSfUZLcVnuHuoh3HSEeS7Lsm-uKd01hjK-LZT7EWNkm1pEmS4LMaO3V4ZG44aoIAIo7uqkqoiImgg35U26L0VPlNANAecpcQZTcEpbAznmyeZgq4KPG2CohGL e_JRFVRFVE2TfQHo0B8mYNg466YtNNCpuumqCIiPVSIl2REROqqugMbSK7QrhjOzLfrlPr0RlxWXpVOktSmwdHZVbI2iJEJEVF2XroDKaAaAw9cuK37Yg_Z3LXadb1O59vzqlKaisqa9eKG6Qoq_2TQH8beuq2LuhHUrUuOmXNT2nFZdm0uU1LaBxEReBGyRIhbKi7LoDPaAfPRPnQGJpdfoNccqLVErcCsO0iQsSrNwpLUgor6b7tPo2RK2abL-JbLoDLaAaAotd9x2tV_bu8MJXJRQqh5XxtRafOfdDZI1。等等。等
如何将其转换为在我的ios应用中显示附件。