/**
  * Build the payload for a subscription create / update.
  *
  * @return array
  */
 protected function buildPayload()
 {
     $payload = ['plan' => $this->plan, 'prorate' => $this->prorate, 'quantity' => $this->quantity, 'trial_end' => $this->getTrialEndForUpdate()];
     if ($taxPercent = $this->billable->getTaxPercent()) {
         $payload['tax_percent'] = $taxPercent;
     }
     return $payload;
 }
 /**
  * Build the payload for a subscription create / update.
  *
  * @return array
  */
 protected function buildPayload()
 {
     $payload = ['plan' => $this->plan, 'prorate' => $this->prorate, 'quantity' => $this->quantity];
     if ($trialEnd = $this->getTrialEndForUpdate()) {
         $payload['trial_end'] = $trialEnd;
     }
     if ($taxPercent = $this->billable->getTaxPercent()) {
         $payload['tax_percent'] = $taxPercent;
     }
     if ($billingCycleAnchor = $this->getBillingCycleAnchorForUpdate()) {
         $payload['billing_cycle_anchor'] = $billingCycleAnchor;
     }
     return $payload;
 }