add buffer flush before direct write

Author: Roman-Koshelev

include/fmt/format-inl.h

@@ -1435,6 +1435,7 @@ extern "C" __declspec(dllimport) int __stdcall WriteConsoleW(  //
 FMT_FUNC bool write_console(std::FILE* f, string_view text) {
   int fd = _fileno(f);
   if (!_isatty(fd)) return false;
+  std::fflush(f);
   auto u16 = utf8_to_utf16(text);
   return WriteConsoleW(reinterpret_cast<void*>(_get_osfhandle(fd)), u16.c_str(),
                        static_cast<dword>(u16.size()), nullptr, nullptr) != 0;

include/fmt/ostream.h

@@ -52,6 +52,7 @@ inline bool write_ostream_unicode(std::ostream& os, fmt::string_view data) {
     return false;
 #endif
   if (!c_file) return false;
+  os.flush();
   return write_console(c_file, data);
 }