Resolves the applicable rate from a RateSchedule given a user's volume. Mirrors the backend RateSchedule::resolve logic: finds the highest tier threshold that the volume meets or exceeds, falling back to the base rate.
Resolves the applicable rate from a RateSchedule given a user's volume. Mirrors the backend RateSchedule::resolve logic: finds the highest tier threshold that the volume meets or exceeds, falling back to the base rate.