Fix node method calls

[acdamiani]

Should fix #23? Still need to do some testing.

[ijisthee]

A comment here would be nice to understand

_node != null && value.Index - _node.Index < 0

[ijisthee]

This nice to ensure that this is always called when the next code is set.

[ijisthee]

cannot test before sunday but the changes look good from here.

[ijisthee]

private void StepOut(ExecutableNode node)
{
    UnityEngine.Debug.Log($"Node: {node}");
    UnityEngine.Debug.Log($"node.Memory: {node.Memory}");
    UnityEngine.Debug.Log($"Agent: {Agent}");
    UnityEngine.Debug.Log($"Agent.GetInstanceID(): {Agent.GetInstanceID()}");

    if (!node.Memory.TryGetValue(Agent.GetInstanceID(), out object memory))
        return;

    // [...]
}

Results in:

This happens directly at tree initialization.
context.node = nodes.FirstOrDefault(x => x.nodeType == ExecutableNode.ExecutableNodeType.Root);

Since you call FirstOrDefault, a bit defensive programming could help here I recommend.

I've added

if (!node) 
  return;

before

if (!node.Memory.TryGetValue(Agent.GetInstanceID(), out object memory))
        return;

Then the error disappears but then the tree doesn't run properly anymore. I'm using Wait nodes and they don't seem to use the memory anymore. With 10 enemies I'm having 10 FPS and the tree runs more than 250 times (my setting) per fps with only wandering node and 2 conditionals (both with self abort) active. When they recognize me, the fps counter shows less than 1 fps.

Something is going on there. Maybe it has to do something with the Node Memory or the conditional memory.