@Override
  public long calculateRamSize() {
    return INSTANCE_SIZE
        + RamUsageEstimator.sizeOfMap(
            deviceToIndex, RamUsageEstimator.shallowSizeOfInstance(Integer.class))
        + RamUsageEstimator.sizeOf(startTimes)
        + RamUsageEstimator.sizeOf(endTimes);
  }
Deserialize TimeIndex and get devices only.

@param inputStream inputStream
@return device name
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/tsfile/timeindex/ArrayDeviceTimeIndex.java