void waitUntilActiveLeaderElected() throws InterruptedException {
      Retriable.attemptUntilTrue(
          () -> servers.stream().anyMatch(server -> server.isLeader(gid)),
          600,
          TimeDuration.valueOf(100, TimeUnit.MILLISECONDS),
          "wait leader elected",
          null);
    }
A Mini Raft CLuster Wrapper for Test Env.
iotdb-core/consensus/src/test/java/org/apache/iotdb/consensus/ratis/TestUtils.java