How to tell when Metal is "done" with an id<MTLTexture>, so we can release it properly.

We have a production Metal app with a complex multithreaded Metal pipeline.

When everything is operating smoothly, it works great. Even when extremely overloaded, it does not crash for days at a time. This isn't good enough for our users.

Unfortunately, when I have zero visibility into id<MTLTexture>, I have no way of knowing when metal is "done" with an id<MTLTexture>.

When overloaded, stale metal render passes need to be 'aborted', which results in metal callbacks not being called.

for example, these callbacks may not be called after an aborted pass:

   id<MTLCommandBuffer> m_cmdbuf;
    [m_cmdbuf addScheduledHandler:^(id <MTLCommandBuffer> cb)         {
       cpr->scheduled = MachAbsoluteTime();
    }];

    [m_cmdbuf addCompletedHandler:^(id <MTLCommandBuffer> cb)         {
        cpr->completed = MachAbsoluteTime();
    }];
    

For the moment, our workaround is a system which waits a few seconds after we "think" a rendering pass should be done with all its (aborted) resources before releasing buffers. This is not ideal, to say the least.

So, in summary, my question is, it would be nice to be able to 'query' an id<MTLTexture> to know when metal is done with it, so that we know that its safe to release it along with our own internal resources.

Is there any such (undocumented) mechanism? I have exhaustively read all existing Metal documentation many times.

An idea that I've been toying with... it would be nice to have something akin to Zombie detection running all the time for id<MTLTexture> only.

In OpenGL, it was OK to use a released texture... you may display a bad frame, but not CRASH!. Is there any similar option for id<MTLTexture>?