Rust

Fix count on null values #273

Job	Run time
cargo test (macos)	5m 4s
Check cargo fmt	36s
cargo check	11m 12s
build with wasm-pack	2m 41s
cargo test (macos-aarch64)	10m 3s
Verify MSRV (Min Supported Rust Version)	8m 44s
Verify Vendored Code	49s
cargo test (win64)	10m 52s
cargo test (amd64)	6m 54s
cargo test datafusion-cli (amd64)	4m 17s
clippy	4m 10s
cargo doc	4m 19s
check Cargo.toml formatting	2m 56s
cargo test hash collisions (amd64)	7m 7s
cargo test doc (amd64)	15m 22s
cargo examples (amd64)	13m 11s
Run sqllogictest with Postgres runner	3m 36s
cargo test pyarrow (amd64)	2m 49s
verify benchmark results (amd64)	12m 28s
check configs.md and ***_functions.md is up-to-date	3m 5s
	2h 10m 15s

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