update

ts/bunq.classes.payment.ts

@@ -182,6 +182,14 @@ export class PaymentBuilder {
     return this;
   }
 
+  /**
+   * Set custom request ID (for idempotency)
+   */
+  public customRequestId(requestId: string): this {
+    this.paymentData.request_reference_split_the_bill = requestId;
+    return this;
+  }
+
   /**
    * Allow bunq.to payments
    */