Atomic update

Is it possible to implement atomic updates, so that if a signal receives multiple updates from its dependent signals, it will only emit one signal value if these updates are originally from the same signal update?

For example, let's say signal b and signal c depend on signal a, and signal d depends on both b and c. If there is new signal value sent to signal a, it should trigger only one signal. This is the dependency graph:

    a
  /   \
 b     c
  \   /
    d

As if right now, it triggers twice.

main = do
  cn <- channel 1
  let a = subscribe cn
  let b = (_ + 1) <$> a
  let c = (_ + 3) <$> a
  let d = (+) <$> b <*> c
  let ds = (\x -> [x]) <$> d
  let all = foldp (<>) [] ds
  send cn 100
  runSignal (all ~> show >>> log)

* Build successful.
[204,105,6]

^^^^^^^^^^^ Expect to be [204, 6], but got [204,105,6]. 204 = (100 + 1) + (100 + 3) 105 = (100 + 1) + (4) 6 = (1 + 1) + (1 + 3)

105 is an intermediate value that could be ignored if supports atomic updates.

Atomic updates is useful for UI rendering optimization. If a view's rendering depends on multiple signals, and they are all updated by the same signal value from their dependencies, atomic updates can make sure the view will only be rerendered once.