UPPER_WRITE_OP
static void enqueue_upper_write_op(APP_CONN *conn, UPPER_WRITE_OP *op)
static int try_write(APP_CONN *conn, UPPER_WRITE_OP *op);
UPPER_WRITE_OP *op = conn->pending_upper_write_head;
static int try_write(APP_CONN *conn, UPPER_WRITE_OP *op)
UPPER_WRITE_OP *op = calloc(1, sizeof(UPPER_WRITE_OP));
UPPER_WRITE_OP *op, *next_op;
UPPER_WRITE_OP *pending_upper_write_head, *pending_upper_write_tail;