Merge pull request #12427 from Chocobo1/io

Avoid inefficient behavior

src/base/utils/io.cpp

@@ -41,10 +41,12 @@ Utils::IO::FileDeviceOutputIterator::FileDeviceOutputIterator(QFileDevice &devic
 
 Utils::IO::FileDeviceOutputIterator::~FileDeviceOutputIterator()
 {
+    if (m_buffer.use_count() == 1) {
         if (m_device->error() == QFileDevice::NoError)
             m_device->write(*m_buffer);
         m_buffer->clear();
     }
+}
 
 Utils::IO::FileDeviceOutputIterator &Utils::IO::FileDeviceOutputIterator::operator=(const char c)
 {