const DefaultInterval = 5 * time.Minute

type ReloadOpts[T any] struct {
	// Read is called to obtain the data to be unmarshaled; e.g. by reading
	// from a file, or making a network request, etc.
	//
	// An error from this function is fatal when calling New, but only a
	// warning during reload.
	//
	// This value is required.
	Read func(context.Context) ([]byte, error)

	// Unmarshal is called with the data that the Read function returns and
	// should return a parsed form of the given value, or an error.
	//
	// An error from this function is fatal when calling New, but only a
	// warning during reload.
	//
	// This value is required.
	Unmarshal func([]byte) (T, error)

	// Logf is a logger used to print errors that occur on reload. If nil,
	// no messages are printed.
	Logf logger.Logf

	// Interval is the interval at which to reload the given data from the
	// source; if zero, DefaultInterval will be used.
	Interval time.Duration

	// IntervalJitter is the jitter to be added to the given Interval; if
	// provided, a duration between 0 and this value will be added to each
	// Interval when waiting.
	IntervalJitter time.Duration
}