Apparently, only a single WRITABLE/READABLE callback is called at each
servicing. For this reason, we want to keep servicing until we end up
not receiving any callback.
When that happens, we can assume that we can't (or don't want to) write
more, and that there is nothing left to read in the socket buffer.
Found via `codespell -q 3 --skip="./thirdparty,./editor/translations" -I ../godot-word-whitelist.txt`
Whitelist consists of:
```
ang
doubleclick
lod
nd
que
te
unselect
```
