Revert "hold raw header string"

This reverts commit 5bb52fbd8c.

src/client/connection/response/success/error.rs

@@ -5,31 +5,23 @@ use std::{
 
 #[derive(Debug)]
 pub enum Error {
-    Code,
-    ContentType,
-    HeaderLen(usize),
+    Protocol,
+    Mime,
     Utf8Error(Utf8Error),
 }
 
 impl Display for Error {
     fn fmt(&self, f: &mut Formatter) -> Result {
         match self {
-            Self::Code => {
-                write!(f, "Unexpected status code")
-            }
-            Self::ContentType => {
-                write!(f, "Content type required")
-            }
-            Self::HeaderLen(l) => {
-                write!(
-                    f,
-                    "Header length reached protocol limit ({l} of {} bytes max)",
-                    super::super::HEADER_LEN
-                )
-            }
             Self::Utf8Error(e) => {
                 write!(f, "UTF-8 error: {e}")
             }
+            Self::Protocol => {
+                write!(f, "Protocol error")
+            }
+            Self::Mime => {
+                write!(f, "MIME error")
+            }
         }
     }
 }