code: public ApnsPayloadBuilder setSummaryArgumentCount(final Integer summaryArgumentCount) {
          if (summaryArgumentCount != null && summaryArgumentCount < 1) {
              throw new IllegalArgumentException("Summary argument count must be positive.");
          }
  
          this.summaryArgumentCount = summaryArgumentCount;
  
          return this;
      }
docs: <p>Sets the summary argument count for this notification. The summary argument count is:</p>
  
  <blockquote>The number of items the notification adds to the category’s summary format string.</blockquote>
  
  <p>By default, all notifications count as a single "item" in a group of notifications. The summary argument count
  controls how many "items" in a "stack" of notifications are represented by a specific notification.
  If, for example, a notification informed a user that seven new podcasts are available, it might be helpful to set
  the summary argument count to 7. When "stacked," the notification would contribute an item count of 7
  to the total number of notifications reported in the summary string (for example, "7 more podcasts").
  </p>
  
  <p>By default, notifications count as a single "item" in a group of notifications, and so the default
  summary argument count is 1 (even if no summary argument count is specified in the notification payload).
  If specified, summary argument count must be positive.</p>
  
  @param summaryArgumentCount the summary argument count for this notification; if {@code null}, the
  {@code summary-arg-count} key is omitted from the payload entirely
  
  @return a reference to this payload builder
  
  @see <a href=
  "https://developer.apple.com/documentation/usernotifications/unnotificationcontent">
  UNNotificationContent</a>
  
  @since 0.13.6