public File getWalFile() {
    return walFile;
  }
Open the read file channel for this wal entry, this method will retry automatically when the
file is sealed when opening the file channel.

@throws IOException failing to open the file channel.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/wal/utils/WALEntryPosition.java