Calculation loading is complex because different calculations can
depend on differently parameterized things. FOr example:
```elixir
def load(_, _, _), do: [foo: %{arg: 1}]
def load(_, _, _), do: [foo: %{arg: 2}]
```
The previous naive implementation would simply merge all of the calculation loads, which naturally would not work. Now we ensure that we load each requirement in isolation.
We now only start tasks once the synchronous work is done as anything
synchronous should be fast, generally.
Additionally, if there is only one task that we are about to start,
we can be confident that all we're going to do is wait for it,
so we can simply run it synchronously
