Returns the result of the computation. By default,
returns {@code null}, which is appropriate for {@code Void}
actions, but in other cases should be overridden, almost
always to return a field or function of a field that
holds the result upon completion.
Returns the result of the computation. By default, returns {@code null}, which is appropriate for {@code Void} actions, but in other cases should be overridden, almost always to return a field or function of a field that holds the result upon completion.
@return the result of the computation