Introduces an **internal**, **experimental** `profiler` function, which
the runtime invokes around user code, including before and after:
- Running the template function of a component
- Executing a lifecycle hook
- Evaluating an output handler
The `profiler` function invokes a callback set with the global
`ng.ɵsetProfiler`. This API is **private** and **experimental** and
could be removed or changed at any time.
This implementation is cheap and available in production. It's cheap
because the `profiler` function is simple, which allows the JiT compiler
to inline it in the callsites. It also doesn't add up much to the
production bundle.
To listen for profiler events:
```ts
ng.ɵsetProfiler((event, ...args) => {
// monitor user code execution
});
```
PR Close#41255
520ff69854