Slight (3 ns) speed improvement thanks to JohnH in https://users.rust…

…-lang.org/t/code-speed-optimization-please/30170

src/header/name.rs

@@ -1072,9 +1072,7 @@ fn parse_hdr<'a>(
         len if len > 64 => Ok(HdrName::custom(data, false)),
         len => {
             // Read from data into the buffer - transforming using `table` as we go
-            for i in 0..len {
-                b[i] = table[data[i] as usize]
-            }
+            data.iter().zip(b.iter_mut()).for_each(|(index, out)| *out = table[*index as usize]);
             match &b[0..len] {
                 b"te" => Ok(Te.into()),
                 b"age" => Ok(Age.into()),