A function which implements logic to determine whether a given Order is eligible for a particular shipping method. Once a ShippingMethod has been assigned to an Order, this function will be called on every change to the Order (e.g. updating quantities, adding/removing items etc).
If the code running in this function is expensive, then consider also defining a ShouldRunCheckFn to avoid unnecessary calls.
type CheckShippingEligibilityCheckerFn<T extends ConfigArgs> = ( ctx: RequestContext, order: Order, args: ConfigArgValues<T>, method: ShippingMethod ) => boolean | Promise<boolean>