def read_from_blobs_file(entry)
      begin
        raw = File.read(@blobs_file_name, entry[BYTES], entry[START])
      rescue => e
        PEROBS.log.fatal "Cannot read blobs file #{@blobs_file_name}: " +
          e.message
      end
      if Zlib.crc32(raw, 0) != entry[CRC]
        PEROBS.log.fatal "BTreeBlob for object #{entry[ID]} has been " +
          "corrupted: Checksum mismatch"
      end

      raw
    end
def read_from_blobs_file(entry)
      begin
        raw = File.read(@blobs_file_name, entry[BYTES], entry[START])
      rescue => e
        PEROBS.log.fatal "Cannot read blobs file #{@blobs_file_name}: " +
          e.message
      end
      if Zlib.crc32(raw, 0) != entry[CRC]
        PEROBS.log.fatal "BTreeBlob for object #{entry[ID]} has been " +
          "corrupted: Checksum mismatch"
      end

      raw
    end
Read _bytes_ bytes from the file starting at offset _address_.
 @param entry [Array] Index entry for the object
 @return [String] Raw bytes of the blob.