the append result "data" is now using the same as param input "data".
when a cached file which size is more than 32768 there are more than one Write() invoked
the cached "data" will be changed when next Write() arrived,as []byte in golang is a ref type
the append result "data" is now using the same as param input "data". when a cached file which size is more than 32768 there are more than one Write() invoked the cached "data" will be changed when next Write() arrived,as []byte in golang is a ref type