Implement Happy Eyeballs connection RFC #1835

Job	Run time
build_versions (stable)	30s
build_versions (beta)	29s
cargo-deny (aarch64-apple-ios)	21s
Docs	22s
build_versions (1.61.0)	58s
cargo-deny (aarch64-linux-android)	19s
Test	51s
Test (json)	1m 0s
cargo-deny (i686-pc-windows-gnu)	19s
Lint	14s
Test (charset)	39s
cargo-deny (i686-pc-windows-msvc)	18s
Test (cookies)	42s
cargo-deny (i686-unknown-linux-gnu)	18s
Test (socks-proxy)	37s
cargo-deny (wasm32-unknown-unknown)	20s
Test (native-certs)	50s
cargo-deny (x86_64-apple-darwin)	19s
Test (gzip)	37s
cargo-deny (x86_64-apple-ios)	21s
Test (brotli)	50s
cargo-deny (x86_64-pc-windows-gnu)	21s
Test (http-crate)	37s
cargo-deny (x86_64-pc-windows-msvc)	20s
Test (http-interop)	41s
cargo-deny (x86_64-unknown-linux-gnu)	23s
Test (http-crate http-interop)	40s
cargo-deny (x86_64-unknown-redox)	17s
Test (tls)	46s
Test (tls, json)	1m 2s
Test (tls, charset)	43s
Test (tls, cookies)	1m 4s
Test (tls, socks-proxy)	42s
Test (tls, native-certs)	44s
Test (tls, gzip)	42s
Test (tls, brotli)	52s
Test (tls, http-crate)	51s
Test (tls, http-interop)	43s
Test (tls, http-crate http-interop)	1m 5s
Test (native-tls)	52s
Test (native-tls, json)	49s
Test (native-tls, charset)	49s
Test (native-tls, cookies)	1m 2s
Test (native-tls, socks-proxy)	39s
Test (native-tls, native-certs)	42s
Test (native-tls, gzip)	43s
Test (native-tls, brotli)	44s
Test (native-tls, http-crate)	41s
Test (native-tls, http-interop)	53s
Test (native-tls, http-crate http-interop)	56s
	32m 37s

Provide feedback