Add file-stream examples #5097

Job	Run time
check	42s
cargo-public-api-crates (axum)	43s
check-docs	18s
cargo-hack	3m 5s
cargo-public-api-crates (axum-core)	20s
cargo-deny check (advisories)	26s
cargo-public-api-crates (axum-extra)	29s
dependencies-are-sorted	18s
cargo-deny check (bans licenses sources)	25s
Spell Check with Typos	6s
cargo-public-api-crates (axum-macros)	24s
test-msrv	1m 53s
test-versions (stable)	1m 43s
armv5te-unknown-linux-musleabi	31s
test-versions (beta)	1m 14s
test-docs	1m 37s
test-nightly	1m 12s
wasm32-unknown-unknown	19s
	15m 45s

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