Handle encrypted SNI

[ameshkov]

And here we go:
https://blog.mozilla.org/security/2018/10/18/encrypted-sni-comes-to-firefox-nightly/

[GauthierPLM]

Has any progress been announced? I enabled ESNI with NextDNS (NextDNS Windows client, NextDNS configured in Firefox, ESNI enabled) and Adguard does not seem to have any issue with this configuration, which use DoH on a system and browser level + ESNI.

I currently use Adguard on Windows v7.3 Nightly 25.

[ameshkov]

@GauthierPLM we're still waiting for the ESNI specification to stabilize.

The version that Firefox and Cloudflare currently use is quite different from the current state of the specification, and the spec is still changing.

[sfionov]

Implemented ECH client in CoreLibs 1.11 (#1565)