Add read-flash support #388

Job	Run time
Check lib (x86_64-unknown-linux-gnu)	1m 2s
Check lib (aarch64-unknown-linux-gnu)	1m 36s
Clippy (x86_64-unknown-linux-gnu)	59s
Unit Tests (x86_64-unknown-linux-gnu)	46s
Check lib (armv7-unknown-linux-gnueabihf)	1m 37s
Check (x86_64-apple-darwin)	44s
Clippy (aarch64-unknown-linux-gnu)	2m 8s
Unit Tests (aarch64-unknown-linux-gnu)	1m 55s
Check (x86_64-unknown-linux-gnu)	40s
Clippy (armv7-unknown-linux-gnueabihf)	1m 54s
Unit Tests (armv7-unknown-linux-gnueabihf)	1m 52s
Check (x86_64-unknown-linux-musl)	38s
Check MSRV (x86_64-unknown-linux-gnu)	51s
Check (x86_64-pc-windows-msvc)	2m 35s
Check MSRV (aarch64-unknown-linux-gnu)	2m 8s
Rustfmt	8s
Check (aarch64-unknown-linux-gnu)	1m 35s
Check MSRV (armv7-unknown-linux-gnueabihf)	1m 53s
Check (armv7-unknown-linux-gnueabihf)	2m 2s
	27m 3s

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