/*!
* @class ExternalConfigSize
*
* @headerfile <seqan/file.h>
*
* @brief Arbitrary size type configuration for @link ExternalString @endlink.
*
* @signature template <typename TSize[, typename TFile[, unsigned
* SEQAN_PAGESIZE[, unsigned FRAMEs]]]> class ExternalConfigSize;
*
* @tparam TSize The size type of the ExternalString.
* @tparam TFile Type of file the ExternalString will be based on. Defaults to
* <tt>File<></tt>.
* @tparam SEQAN_PAGESIZE The number of values in one page. This should be a
* power of 2 to speed up transfer and calculations.
* Default: 2<sup>20</sup>.
* @tparam FRAMES The number of pages that should reside in internal memory. To
* enable prefetching and automatic swap-out, <tt>frames</tt>
* should be greater than 1. Default: 2.
*/