Rust

organize ExternalSorter fields #195

Job	Run time
build with wasm-pack	3m 26s
cargo check	12m 13s
cargo test (macos)	12m 3s
Check License Header	2m 19s
cargo test (macos-aarch64)	10m 33s
cargo test (win64)	1h 10m 35s
Check cargo fmt	40s
Verify Vendored Code	50s
Verify MSRV (Min Supported Rust Version)	9m 2s
cargo test doc (amd64)	16m 38s
cargo test (amd64)	11m 49s
cargo examples (amd64)	14m 15s
cargo test datafusion-cli (amd64)	4m 18s
check Cargo.toml formatting	3m 3s
check configs.md and ***_functions.md is up-to-date	3m 31s
clippy	6m 25s
cargo test hash collisions (amd64)	18m 21s
cargo doc	4m 26s
Run sqllogictest with Postgres runner	3m 49s
verify benchmark results (amd64)	13m 10s
cargo test pyarrow (amd64)	3m 5s
	3h 44m 31s

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