Add support for timestamp encoding in exemplars #950

Job	Run time
Test Suite	1m 59s
Check	1m 37s
Check rustdoc intra-doc links	34s
Rustfmt	23s
Clippy	1m 26s
Cross compile (powerpc-unknown-linux-gnu)	21s
Cross compile (wasm32-unknown-unknown)	18s
Cross compile (armv7-unknown-linux-gnueabihf)	22s
Cross compile (powerpc64-unknown-linux-gnu)	20s
	7m 20s

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