- Export socket field of AsyncHttpServer and addHeaders proc for templates
- Make respond a template instead of proc because of how often it's called.
This means no more "await" when invoking it.
- Optimize respond template with special case for empty headers and
Content-Length entry
- newRequest doesn't allocate a hostname and body anymore because they're
copied in later
- Major changes to processClient to prevent allocations and copies
477b3594eb