Parameter names (the action's spelling) whose values came from a binding.
False when the run binds nothing on this action, so the caller can keep today's path exactly.
Keys the model supplied for a bound parameter. Their values were discarded.
The parameters to dispatch: the model's, minus every bound name, plus each bound value under the action's own spelling of the parameter. With no bindings this is the model's object itself.
Why the call must not be dispatched, or null when it may proceed.
The outcome of applying one action's bindings to one call.