@Override
  public String toString() {
    StringBuilder sb = new StringBuilder();
    sb.append(getClass().getSimpleName()).append("[");
    sb.append("tableName=").append(tn).append(", currentSnapshots=");
    sb.append(currentSnapshots).append(", lastFullCompute=").append(lastFullCompute);
    return sb.append("]").toString();
  }
Extracts the size component from a serialized {@link SpaceQuotaSnapshot} protobuf.
@param r A Result containing one cell with a SpaceQuotaSnapshot protobuf
@return The size in bytes of the snapshot.
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/FileArchiverNotifierImpl.java