Change response header key

handler_utils/request.go

@@ -46,7 +46,7 @@ func AddRequestIDToHeaders(requestID *string, responseHeaders map[string]string,
 	for key, val := range requestHeaders {
 		// Don't be case-sensitive
 		if strings.ToLower(key) == strings.ToLower(HTTPXRequestIDHeaderValue) {
-			responseHeaders[key] = val
+			responseHeaders[HTTPXRequestIDHeaderValue] = val
 			break
 		}
 	}