Add AgentBuilder::timeout to FUTURE.md #1807

Job	Run time
build_versions (stable)	13s
build_versions (beta)	51s
build_versions (1.61.0)	17s
Test	42s
Test (json)	45s
Test (charset)	37s
Lint	16s
Test (cookies)	42s
Test (socks-proxy)	41s
Test (native-certs)	39s
cargo-deny (aarch64-apple-ios)	18s
Test (gzip)	40s
cargo-deny (aarch64-linux-android)	27s
Docs	26s
Test (brotli)	37s
cargo-deny (i686-pc-windows-gnu)	19s
Test (http-crate)	46s
cargo-deny (i686-pc-windows-msvc)	18s
cargo-deny (i686-unknown-linux-gnu)	19s
Test (http-interop)	37s
Test (http-crate http-interop)	38s
cargo-deny (wasm32-unknown-unknown)	18s
Test (tls)	42s
cargo-deny (x86_64-apple-darwin)	19s
Test (tls, json)	53s
cargo-deny (x86_64-apple-ios)	18s
Test (tls, charset)	40s
Test (tls, cookies)	45s
cargo-deny (x86_64-pc-windows-gnu)	21s
Test (tls, socks-proxy)	45s
cargo-deny (x86_64-pc-windows-msvc)	22s
Test (tls, native-certs)	1m 0s
cargo-deny (x86_64-unknown-linux-gnu)	18s
Test (tls, gzip)	41s
Test (tls, brotli)	1m 3s
cargo-deny (x86_64-unknown-redox)	20s
Test (tls, http-crate)	45s
Test (tls, http-interop)	56s
Test (tls, http-crate http-interop)	54s
Test (native-tls)	39s
Test (native-tls, json)	1m 5s
Test (native-tls, charset)	57s
Test (native-tls, cookies)	45s
Test (native-tls, socks-proxy)	42s
Test (native-tls, native-certs)	44s
Test (native-tls, gzip)	43s
Test (native-tls, brotli)	49s
Test (native-tls, http-crate)	53s
Test (native-tls, http-interop)	44s
Test (native-tls, http-crate http-interop)	48s
	31m 17s

Provide feedback