Constant MAX_CFB1_CHUNK_LEN 

const MAX_CFB1_CHUNK_LEN: usize = _; // 1_152_921_504_606_846_976usize

Bounds one AES_cfb1_encrypt call so the byte-to-bit conversion cannot overflow, which it would above usize::MAX / 8 = 512 MiB (on a 32-bit target). Mirrors MAXBITCHUNK in AWS-LC’s crypto/decrepit/cfb/cfb.c.