RenderContext passed into StatefulWorkflow#render is new instance every time

[weverb2]

RenderContext passed into StatefulWorkflow#render is new instance every time

[steve-the-edwards]

Problem first noted in #849 then we tried to fix in #850 but this had a bug because we were recreating anyway in order to get the StateT info in.

I believe the reason we have these StatefulWorkflow.RenderContext and StatelessWorkflow.RenderContext concrete types that just delegate to the BaseRenderContext instance passed in (which is a RealRenderContext) is so that StatelessWorkflows don't have to worry about typing the StateT.

That being said, we always cast to a StatefulWorkflow when creating the nodes (see asStatefulWorkflow) so by the time we create the node I don't see why we can't do the cast write away for the RenderContext and only deal with that.

Will spike on this.

[steve-the-edwards]

Note that to currently handle this for lambdas passed in teh rendering to Composables, we box the lambdas on the Compose side like so:

@Composable
fun rememberLambda(lambda: () -> Unit): () -> Unit {
  val latestLambda = rememberUpdatedState(lambda)
  return remember { { latestLambda.value.invoke() } }
}

So that we save the latest lambda but hide it from the other Composables until its invoked.

[steve-the-edwards]

Consider "Strong Skipping" - as discussed here - may make instance equality all we need for skipping - https://www.reddit.com/r/androiddev/comments/1an5emm/comment/kqf8dz0/