private static QuorumInfo defaultQuorumInfo(boolean emptyOptionals) {
        return new QuorumInfo(1, 1, 1L,
                singletonList(new QuorumInfo.ReplicaState(1,
                        emptyOptionals ? Uuid.ZERO_UUID : REPLICA_DIRECTORY_ID,
                        100,
                        emptyOptionals ? OptionalLong.empty() : OptionalLong.of(1000),
                        emptyOptionals ? OptionalLong.empty() : OptionalLong.of(1000))),
                singletonList(new QuorumInfo.ReplicaState(1,
                        emptyOptionals ? Uuid.ZERO_UUID : REPLICA_DIRECTORY_ID,
                        100,
                        emptyOptionals ? OptionalLong.empty() : OptionalLong.of(1000),
                        emptyOptionals ? OptionalLong.empty() : OptionalLong.of(1000))),
                singletonMap(1, new QuorumInfo.Node(1, Collections.emptyList())));
    }
Test if admin client can be closed in the callback invoked when
an api call completes. If calling {@link Admin#close()} in callback, AdminClient thread hangs
clients/src/test/java/org/apache/kafka/clients/admin/KafkaAdminClientTest.java