Refactor: Extract type alias from examples #4272

Job	Run time
lint	12m 2s
cluster-benchmark (cluster_benchmark)	46s
examples (stable, memstore)	38s
openraft-feature-test (nightly)	54s
examples (stable, raft-kv-memstore)	2m 35s
openraft-feature-test (nightly, serde)	52s
openraft-test-bench (nightly)	1m 1s
examples (stable, raft-kv-memstore-grpc)	1m 50s
openraft-test (stable, 0)	3m 14s
openraft-feature-test (nightly, single-term-leader)	48s
examples (stable, raft-kv-memstore-network-v2)	53s
openraft-test (nightly, 30)	3m 27s
openraft-feature-test (nightly, single-term-leader,serde,singlethreaded)	51s
rt-monoio	45s
openraft-test (nightly, 0, single-term-leader)	3m 11s
examples (stable, raft-kv-memstore-opendal-snapshot-data)	1m 15s
examples (stable, raft-kv-memstore-singlethreaded)	51s
examples (stable, raft-kv-rocksdb)	8m 6s
Build (nightly, bench,serde,bt,singlethreaded)	48s
tests-feature-test (nightly)	2m 59s
stores (stores/memstore)	55s
examples (nightly, memstore)	55s
stores (stores/rocksstore)	6m 15s
tests-feature-test (nightly, single-term-leader)	3m 1s
examples (nightly, raft-kv-memstore)	2m 22s
examples (nightly, raft-kv-memstore-grpc)	1m 48s
examples (nightly, raft-kv-memstore-network-v2)	1m 4s
examples (nightly, raft-kv-memstore-opendal-snapshot-data)	1m 32s
examples (nightly, raft-kv-memstore-singlethreaded)	1m 10s
examples (nightly, raft-kv-rocksdb)	12m 28s
	1h 19m 16s

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