feat: Xample cancel transaction (#7)

Author: nahimterrazas

examples/evm/cancelTransactionById.ts

@@ -0,0 +1,33 @@
+/**
+ * Cancel Relayer Transaction By Id Example
+ *
+ * This example demonstrates how to use the OpenZeppelin Relayer SDK to cancel a relayer transaction by id.
+ *
+ * IMPORTANT: This is provided as a demonstration only. For production use:
+ * - Use proper error handling and transaction confirmation checks
+ * - Implement appropriate security measures for API keys and tokens
+ * - Consider rate limiting and monitoring for production applications
+ * - Test thoroughly on devnet/testnet before using on mainnet
+ * - Use https connection for production applications
+ *
+ * Usage:
+ *   ts-node cancelTransactionById.ts
+ */
+import { Configuration, RelayersApi } from '../../src';
+
+// example dev config
+const config = new Configuration({
+  basePath: 'http://localhost:8080',
+  accessToken: 'Bearer example-123456',
+});
+
+const relayersApi = new RelayersApi(config);
+
+const relayer_id = 'sepolia-example';
+
+const transaction_id = '305ff83d-6653-465f-8fa3-e8a46271fb83';
+
+relayersApi
+  .cancelTransaction(relayer_id, transaction_id)
+  .then((transaction) => console.log(JSON.stringify(transaction.data, null, 2)))
+  .catch(console.error);