4a1e83d6be
Fixes #20862 With the change in60af2f3cb2the bookkeep for buffer memory was changed subtly, the problem here that we would shrink buffer size before we after flush use said buffer's size to decrement the buffer_list_bytes value, previously inc:ed by the full, allocated size. I.e. we would slowly grow this value instead of adjusting properly to actual used bytes. Test included. (cherry picked from commitee5e71172f) Closes scylladb/scylladb#20914