private static long getPageAddress(int pageIndex) {
    return (SchemaFileConfig.PAGE_INDEX_MASK & pageIndex) * SchemaFileConfig.PAGE_LENGTH
        + SchemaFileConfig.FILE_HEADER_SIZE;
  }
Only accessed during write operation and every page returned is due to be modified thus they
are all marked dirty.

@param size size of the expected segment
@return always write locked
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/schemaengine/schemaregion/mtree/impl/pbtree/schemafile/pagemgr/PageManager.java