fix(headers): Support multiple Content-Length values on same line (#2471)

Closes #2470

tests/client.rs

@@ -1043,6 +1043,30 @@ test! {
         error: |err| err.to_string() == "request has unsupported HTTP version",
 }
 
+test! {
+    name: client_handles_contentlength_values_on_same_line,
+
+    server:
+        expected: "GET /foo HTTP/1.1\r\nhost: {addr}\r\n\r\n",
+        reply: "\
+            HTTP/1.1 200 OK\r\n\
+            Content-Length: 3,3\r\n\
+            Content-Length: 3,3\r\n\
+            \r\n\
+            abc\r\n",
+
+    client:
+        request: {
+            method: GET,
+            url: "http://{addr}/foo",
+        },
+        response:
+            status: OK,
+            headers: {
+            },
+            body: &b"abc"[..],
+}
+
 mod dispatch_impl {
     use super::*;
     use std::io::{self, Read, Write};