max future trigger overkill

[hjoliver]

We automatically raise the runahead limit to accommodate "future triggers", by an amount equal to the largest future trigger offset in the task pool. However, that's overkill if the tasks involved are not actually at the runahead limit.

[oliver-sanders]

Is this documented?

[hjoliver]

For users? I don't think it is. We should do that while we're at it (fixing this issue, that is).