Update stdout_sinks-inl.h

include/spdlog/sinks/stdout_sinks-inl.h

@@ -47,6 +47,7 @@ SPDLOG_INLINE void stdout_sink_base<ConsoleMutex>::log(const details::log_msg &m
     memory_buf_t formatted;
     formatter_->format(msg, formatted);
 #ifdef _WIN32
+    ::fflush(file_); // flush in case there is somthing in this file_ already
     auto size = static_cast<DWORD>(formatted.size());
     DWORD bytes_written = 0;
     bool ok = ::WriteFile(handle_, formatted.data(), size, &bytes_written, nullptr) != 0;