Rust

add downcast_delegate #630

Job	Run time
linux build test	6m 48s
cargo test (macos-aarch64)	7m 1s
build and run with wasm-pack	6m 30s
Verify MSRV (Min Supported Rust Version)	5m 34s
Verify Vendored Code	1m 36s
Check cargo fmt	1m 33s
Run sqllogictest with Postgres runner	8m 11s
cargo check datafusion-functions features	3m 0s
check Cargo.toml formatting	3m 53s
check example README is up-to-date	5m 19s
cargo check datafusion-substrait features	11m 57s
cargo check datafusion features	12m 7s
cargo check datafusion-common features	2m 13s
cargo test datafusion-cli (amd64)	5m 12s
Run sqllogictest in Substrait round-trip mode	7m 3s
cargo test doc (amd64)	7m 35s
cargo test (amd64)	13m 7s
cargo doc	5m 24s
cargo examples (amd64)	15m 1s
cargo check datafusion-proto features	5m 5s
verify benchmark results (amd64)	15m 15s
clippy	8m 1s
check configs.md and ***_functions.md is up-to-date	7m 37s
	2h 45m 2s

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