Streaming large HTTP response fix
- Fixes a potential heap-use-after-free when finishing (tryEnd, end) an Http response within onWritable callback (captured variables are destroyed).
- Affects only users who stream large Http responses with the use of onWritable callback. If your application never sets an onWritable callback, then you're not affected.
- See uWebSockets.js/examples/VideoStreamer.js for an example of affected use.