docs: public void setTransitGatewayVpcAttachments(java.util.Collection<TransitGatewayVpcAttachment> transitGatewayVpcAttachments) {
          if (transitGatewayVpcAttachments == null) {
              this.transitGatewayVpcAttachments = null;
              return;
          }
  
          this.transitGatewayVpcAttachments = new com.amazonaws.internal.SdkInternalList<TransitGatewayVpcAttachment>(transitGatewayVpcAttachments);
      }