Compositor_FrameTiming

Provides a single frame's timing information to the app

struct Compositor_FrameTiming
{
    uint32_t size; // sizeof(Compositor_FrameTiming)
    double frameStart;
    float frameVSync; // seconds from frame start
    uint32_t droppedFrames;
    uint32_t frameIndex;
    vr::TrackedDevicePose_t pose;
};