Currently, to specify a allowedLateness of zero, you still need to specify a size and unit, like below:

$tumblingWindow: {
  allowedLateness: {size: 0 , unit: "minute",}
  ...
}

We want to support the following, this was mentioned in the original syntax/scope doc:

$tumblingWindow: {
  allowedLateness: 0
  ...
}

We also want to support this for the idleTimeout field.