deferFirstFrame method
Tell the framework to not send the first frames to the engine until there is a corresponding call to allowFirstFrame.
Call this to perform asynchronous initialization work before the first frame is rendered (which takes down the splash screen). The framework will still do all the work to produce frames, but those frames are never sent to the engine and will not appear on screen.
Calling this has no effect after the first frame has been sent to the engine.
Implementation
void deferFirstFrame() {
assert(_firstFrameDeferredCount >= 0);
_firstFrameDeferredCount += 1;
}