dillon1000/react

[runtime] useRenderCounter

--- 

(`react-forget-runtime` package seems to be synced to -.) 

RFC: useRenderCounter hook: 

- tracks # renders (increments on render path) 

- exposes a global renderCounterRegistry (counting # renders in alive / mounted 
components) 

Next PR will modify BabelPlugin to add codegen 

```js 

// Similar to how we're currently importing `isForgetEnabled` 

import {isInstrumentForgetEnabled_Secret} from "ReactForgetFeatureFlag"; 

// ... 

function Component_uncompiled(props) { 

if (isInstrumentForgetEnabled_Secret) { 

useRenderCounter(); 

} 

// ... 

} 

function Component_forget(props) { 

if (isInstrumentForgetEnabled_Secret) { 

useRenderCounter(); 

} 

// ... 

} 

```