Run, discard the final state, and return the final value in the context of F
Calls eval using Monoid[S].zero as the initial state
Run, discard the final value, and return the final state in the context of F
Calls exec using Monoid[S].zero as the initial state
Calls run using Monoid[S].zero as the initial state
Discards the writer component.
A monad transformer stack yielding
(R, S1) => F[(W, A, S2)].