private boolean isLeaderReady() {
      return isLeaderReady.get();
    }
Get leader ready state, DO NOT use consensus layer's leader ready flag because
SimpleConsensus' ready flag is always {@code true}. Note that this flag has nothing to do
with listening and a {@link PipeTask} starts only iff the current node is a leader and ready.

@return {@code true} iff the current node is a leader and ready
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/pipe/agent/runtime/PipeSchemaRegionListenerManager.java