Rust

add fast-path for `with_new_children` #34

Job	Run time
Verify MSRV (Min Supported Rust Version)	4m 59s
linux build test	2m 53s
Check cargo fmt	1m 8s
Verify Vendored Code	1m 21s
cargo test (macos-aarch64)	6m 46s
build and run with wasm-pack	5m 40s
cargo test (amd64)	0s
verify benchmark results (amd64)	0s
cargo examples (amd64)	0s
cargo check datafusion features	0s
cargo check datafusion-common features	0s
cargo check datafusion-functions features	0s
check example README is up-to-date	0s
cargo check datafusion-proto features	0s
cargo test datafusion-cli (amd64)	0s
check Cargo.toml formatting	0s
check configs.md and ***_functions.md is up-to-date	0s
cargo doc	0s
Run sqllogictest in Substrait round-trip mode	0s
Run sqllogictest with Postgres runner	0s
cargo check datafusion-substrait features	0s
clippy	0s
cargo test doc (amd64)	0s
	22m 47s

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