初步实现功能

include/seafile/api/seafile_api.hpp

@@ -268,7 +268,9 @@ namespace seafile::api {
                 header.emplace("range", range);
                 if (const auto &response = cpr::Get(url, header);
                     response.error || (response.status_code != 200 && response.status_code != 206)) {
-                    return tl::make_unexpected(SeafileException{std::format("HTTP Error:{}", response.status_code)});
+                    return tl::make_unexpected(SeafileException{
+                        std::format("Download bytes range {} failed, HTTP Error:{}", range, response.status_code)
+                    });
                 } else {
                     return response.text;
                 }