The number of blocks of memory in use in this entry. A block of memory is the amount of memory returned by a single call to the memory allocation routine in AOS. Hence the size of a block of memory is variable. This statistic can be used to check for memory leaks. One possible strategy is to note the value, do some operations, undo the operations, then check the value again - the start and end values should match. If they do not, there may be a memory leak.