finish refactor, add docs and CI

include/nxst/domain/transfer_state.hpp

@@ -4,22 +4,22 @@
 #include <string>
 
 struct TransferState {
-    std::atomic<bool>     done{false};
-    std::atomic<bool>     cancelled{false};
-    std::atomic<bool>     connection_failed{false};
+    std::atomic<bool> done{false};
+    std::atomic<bool> cancelled{false};
+    std::atomic<bool> connection_failed{false};
     std::atomic<uint64_t> bytes_done{0};
     std::atomic<uint64_t> bytes_total{0};
 
-    std::string    status;
-    std::string    fail_reason;
+    std::string status;
+    std::string fail_reason;
     mutable std::mutex status_mutex;
 
     void reset() {
-        done              = false;
-        cancelled         = false;
+        done = false;
+        cancelled = false;
         connection_failed = false;
-        bytes_done        = 0;
-        bytes_total       = 0;
+        bytes_done = 0;
+        bytes_total = 0;
         fail_reason.clear();
         std::lock_guard<std::mutex> lock(status_mutex);
         status.clear();