@Override
  @TestOnly
  public void getPageBuffer(ByteBuffer dstBuffer) {
    syncPageBuffer();
    this.pageBuffer.clear();
    dstBuffer.put(this.pageBuffer);
  }
compatible constructor with no existing ref or lock
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/pbtree/schemafile/SchemaPage.java