Method getLogs

ZezeJava/ZezeJavaTest/src/SimpleRaft/Raft.java:50–50

(long indexBegin, long indexEnd)

		Log getLog(long index); // return null if not exist

		@NotNull Log @NotNull [] getLogs(long indexBegin, long indexEnd); // [indexBegin, indexEnd)

		@Nullable Log getLogByKey(long key); // return null if not exist