Rust

Fix to unparse the plan with multiple UNION statements into an SQL st… #65

Job	Run time
Check cargo fmt	38s
cargo check	10m 32s
build with wasm-pack	2m 33s
cargo test (macos)	10m 45s
cargo test (macos-aarch64)	11m 19s
Verify MSRV (Min Supported Rust Version)	7m 2s
Verify Vendored Code	54s
cargo test (win64)	48m 2s
cargo examples (amd64)	13m 19s
cargo test (amd64)	10m 2s
cargo test datafusion-cli (amd64)	4m 0s
clippy	5m 27s
cargo test doc (amd64)	15m 14s
cargo doc	4m 11s
Run sqllogictest with Postgres runner	3m 37s
verify benchmark results (amd64)	12m 22s
check Cargo.toml formatting	2m 48s
check configs.md is up-to-date	2m 47s
cargo test hash collisions (amd64)	14m 51s
cargo test pyarrow (amd64)	2m 58s
	3h 3m 21s

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