cli

parallelize block splitting #54

Job	Run time
Run lints	4m 32s
Run unit tests	6m 6s
Build CLI (aarch64-apple-darwin)	4m 18s
Build CLI (aarch64-unknown-linux-gnu)	4m 5s
Build CLI (aarch64-unknown-linux-musl)	4m 14s
Build CLI (x86_64-apple-darwin)	4m 36s
Build CLI (x86_64-pc-windows-gnu)	4m 52s
Build CLI (x86_64-unknown-linux-gnu)	4m 15s
Build CLI (x86_64-unknown-linux-musl)	4m 10s
Compat test (x86_64-pc-windows-gnu)	9s
Compat test (x86_64-apple-darwin)	10s
Compat test (aarch64-apple-darwin)	7s
Compat test (x86_64-unknown-linux-gnu)	1m 23s
Compat test (x86_64-unknown-linux-musl)	24s
	43m 21s

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