sockets.tcp - redirect to file for Android and iOS

- set `destUri` to non-empty string will open outputStream
- set `destUrl` to empty string will close outputStream
- `close` and `disconnect` will close outputStream
- ~~`readyToRead` is not set to `false` after sending receive event~~ `readToRead` is ignored for redirect to file
- Fixed some style issues from other code reviews
Is this assuming that receive event is only called once?  Will this necessarily be true, or does it just happen to be for small requests?