Rust

add fast-path for `with_new_children` #59

Job	Run time
linux build test	5m 24s
Verify Vendored Code	1m 15s
build and run with wasm-pack	4m 29s
Verify MSRV (Min Supported Rust Version)	4m 48s
Check cargo fmt	1m 7s
cargo test (macos-aarch64)	16m 40s
cargo test datafusion-cli (amd64)	4m 15s
cargo check datafusion features	11m 4s
cargo examples (amd64)	12m 15s
cargo check datafusion-proto features	4m 48s
cargo test (amd64)	11m 1s
cargo check datafusion-substrait features	11m 8s
cargo check datafusion-common features	1m 37s
cargo check datafusion-functions features	3m 8s
clippy	4m 34s
cargo doc	4m 47s
Run sqllogictest with Postgres runner	6m 20s
cargo test doc (amd64)	7m 56s
check Cargo.toml formatting	3m 17s
verify benchmark results (amd64)	10m 47s
check configs.md and ***_functions.md is up-to-date	4m 31s
Run sqllogictest in Substrait round-trip mode	6m 25s
check example README is up-to-date	39s
	2h 22m 15s

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