Implement guess key size.

src/bytes_base64.rs

@@ -35,7 +35,7 @@ impl BytesBase64 {
 
     pub fn to_bytes(&self) -> Bytes {
         let BytesBase64(v) = self;
-        fn chunk_to_bytes(c: &[u8]) -> Vec<u8> {
+        fn to_bytes(c: &[u8]) -> Vec<u8> {
             let mut v = c.to_vec();
             // pad with bytes for conversion
             while v.len() < 4 {
@@ -52,7 +52,7 @@ impl BytesBase64 {
             }
             result
         }
-        Bytes(v.chunks(4).map(|c| chunk_to_bytes(c)).flatten().collect())
+        Bytes(v.chunks(4).map(|c| to_bytes(c)).flatten().collect())
     }
 
     pub fn from_base64(s: &str) -> BytesBase64 {