func (tb *tokenBucket) capacityToken() time.Time {
	return time.Now().Add(-tb.refillDuration).Truncate(tb.tokenInterval)
}
func (tb *tokenBucket) capacityToken() time.Time {
	return time.Now().Add(-tb.refillDuration).Truncate(tb.tokenInterval)
}
func ( tb * tokenBucket ) capacityToken ( ) time . Time { return time . Now ( ) . Add ( - tb . refillDuration ) . Truncate ( tb . tokenInterval ) }
// Determine the historic token timestamp representing a full bucket
Determine the historic token timestamp representing a full bucket