use as_bytes() instead of b

src/main.rs

@@ -187,7 +187,8 @@ fn parse_field_lines(
         reader.read_line(&mut line).unwrap();
 
         if !line.ends_with("\r\n") {
-            b"Lines need to end with a CRLF"
+            "Lines need to end with a CRLF"
+                .as_bytes()
                 .iter()
                 .for_each(|byte| response_body.push(*byte));
 
@@ -212,7 +213,8 @@ fn parse_field_lines(
         let field_line = match line.split_once(":") {
             Some(val) => val,
             None => {
-                b"Invalid field-line"
+                "Invalid field-line"
+                    .as_bytes()
                     .iter()
                     .for_each(|byte| response_body.push(*byte));
 
@@ -236,7 +238,8 @@ fn parse_field_lines(
     }
 
     if !field_lines.contains_key(&String::from("Host")) {
-        b"field-line with key HOST is missing"
+        "field-line with key HOST is missing"
+            .as_bytes()
             .iter()
             .for_each(|byte| response_body.push(*byte));
 
@@ -372,7 +375,8 @@ fn handle_request(mut stream: TcpStream) -> Result<(), Box<dyn Error>> {
     }
 
     if line.ends_with(" ") {
-        b"There is whitespace between the start-line and the first field-line"
+        "There is whitespace between the start-line and the first field-line"
+            .as_bytes()
             .iter()
             .for_each(|byte| response_body.push(*byte));