docs: protected long getBlockSize(final int idNamespace) {
          Preconditions.checkArgument(blockSizer != null, "Blocksizer has not yet been initialized");
          isActive = true;
          long blockSize = blockSizer.getBlockSize(idNamespace);
          Preconditions.checkArgument(blockSize>0,"Invalid block size: %s",blockSize);
          Preconditions.checkArgument(blockSize<getIdUpperBound(idNamespace),
                  "Block size [%s] cannot be larger than upper bound [%s] for partition [%s]",blockSize,getIdUpperBound(idNamespace),idNamespace);
          return blockSize;
      }