Rust

Cherry pick 93ba65a - add downcast_delegate() #629

Job	Run time
Check cargo fmt	1m 10s
build and run with wasm-pack	6m 0s
Verify Vendored Code	1m 34s
cargo test (macos-aarch64)	8m 49s
Verify MSRV (Min Supported Rust Version)	5m 53s
linux build test	7m 8s
cargo test doc (amd64)	8m 42s
cargo check datafusion-substrait features	12m 11s
cargo examples (amd64)	15m 46s
Run sqllogictest with Postgres runner	7m 21s
clippy	7m 13s
cargo check datafusion-common features	1m 57s
verify benchmark results (amd64)	15m 26s
cargo check datafusion-proto features	5m 4s
cargo doc	5m 32s
check configs.md and ***_functions.md is up-to-date	6m 11s
cargo check datafusion-functions features	3m 14s
check example README is up-to-date	6m 46s
cargo test (amd64)	13m 23s
Run sqllogictest in Substrait round-trip mode	8m 33s
cargo test datafusion-cli (amd64)	5m 18s
cargo check datafusion features	12m 4s
check Cargo.toml formatting	4m 43s
	2h 49m 58s

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