numBlockBytesHeader :: Header -> Int
numBlockBytesHeader header =
    let start = headerPageSize + (numMetadataBytesHeader header)
        end =  (fromIntegral $ header ^. recordBlockIndexPos)
    in end - start
numBlockBytesHeader :: Header -> Int
numBlockBytesHeader header =
    let start = headerPageSize + (numMetadataBytesHeader header)
        end =  (fromIntegral $ header ^. recordBlockIndexPos)
    in end - start
numBlockBytesHeader header =
    let start = headerPageSize + (numMetadataBytesHeader header)
        end =  (fromIntegral $ header ^. recordBlockIndexPos)
    in end - start