assess_tau              Assess the statistical feasibility of a
                        proposed truncation time
default_fail_thresholds
                        Default Fail thresholds for feasibility
                        classification
default_feasibility_thresholds
                        Default Pass thresholds for feasibility
                        classification
optimize_tau            Feasibility-constrained utility optimization of
                        the truncation time
twostage_tau            Complete two-stage truncation-time selection
