perf(header): use MemSlice when parsing headers

src/header/common/content_length.rs

@@ -40,6 +40,7 @@ impl Header for ContentLength {
         static NAME: &'static str = "Content-Length";
         NAME
     }
+
     fn parse_header(raw: &Raw) -> ::Result<ContentLength> {
         // If multiple Content-Length headers were sent, everything can still
         // be alright if they all contain the same value, and all parse
@@ -49,9 +50,9 @@ impl Header for ContentLength {
             .fold(None, |prev, x| {
                 match (prev, x) {
                     (None, x) => Some(x),
-                    (e@Some(Err(_)), _ ) => e,
+                    (e @ Some(Err(_)), _ ) => e,
                     (Some(Ok(prev)), Ok(x)) if prev == x => Some(Ok(prev)),
-                    _ => Some(Err(::Error::Header))
+                    _ => Some(Err(::Error::Header)),
                 }
             })
             .unwrap_or(Err(::Error::Header))

src/header/common/retry_after.rs

@@ -179,14 +179,14 @@ mod tests {
 
     #[test]
     fn hyper_headers_from_raw_delay() {
-        let headers = Headers::from_raw(&[httparse::Header { name: "Retry-After", value: b"300" }]).unwrap();
+        let headers = make_header!(b"Retry-After", b"300");
         let retry_after = headers.get::<RetryAfter>().unwrap();
         assert_eq!(retry_after, &RetryAfter::Delay(Duration::seconds(300)));
     }
 
     #[test]
     fn hyper_headers_from_raw_datetime() {
-        let headers = Headers::from_raw(&[httparse::Header { name: "Retry-After", value: b"Sun, 06 Nov 1994 08:49:37 GMT" }]).unwrap();
+        let headers = make_header!(b"Retry-After", b"Sun, 06 Nov 1994 08:49:37 GMT");
         let retry_after = headers.get::<RetryAfter>().unwrap();
         let expected = "Sun, 06 Nov 1994 08:49:37 GMT".parse::<HttpDate>().unwrap();