FLUSH_BLOCK
if (bflush) FLUSH_BLOCK(s, 0);
FLUSH_BLOCK(s, flush == Z_FINISH);
if (bflush) FLUSH_BLOCK(s, 0);
FLUSH_BLOCK(s, flush == Z_FINISH);
FLUSH_BLOCK(s, 0);
FLUSH_BLOCK(s, 0);
FLUSH_BLOCK(s, flush == Z_FINISH);