fix(network): Accommodate async route handler callbacks

[carmanchris31]

fixes #19855

Signed-off-by: Christopher Carman [email protected]

[mxschmitt]

The Playwright project has a generated type layer in between which is actually exposed to the public, it is generated based off the docs and the override-types.

Let us know if you need help, I'd try massaging the docs first, by doing something like - handler <[function]\([Route], [Request]\):[Promise|void]> and run node ./utils/generate_types.

[carmanchris31]

I'll take a look, thanks!