const DIGEST_MAX_INPUT_LEN: u64 = u64::MAX; // 18_446_744_073_709_551_615u64Expand description
SHA-1, SHA-224, and SHA-256 are limited to an input size of 2^64-1 bits. SHA-384, SHA-512, and SHA-512/256 are limited to an input size of 2^128-1 bits according to the spec. u64 is more than sufficient enough for practical usecases, so we limit the input length to 2^64-1 bits.