Copy on write C++ example

copy_on_write<std::vector<EnvelopePoint>> envelope1;
envelope1.write().push_back(EnvelopePoint(0.0,1.0));
envelope1.write().push_back(EnvelopePoint(1.0,0.0));
std::vector<copy_on_write<std::vector<EnvelopePoint>>> copies;
for (int i=0;i<1000000;i++) // some tests i've done actually involve a million HourGlass envelopes and it seems to work fine
{
  copies.push_back(envelope1);
}
// from the 5000th copy of the envelope, read second point's time position
qDebug() << copies[5000].read()[1].TimePosition();
// change time position of the first node of the 999999th copy of the envelope
copies[999998].write()[0].setTimePosition(0.13);