Fix the example.

Author: rkistner

README.md

@@ -65,8 +65,8 @@ void main() async {
   // 1. Atomic persistence (all updates are either applied or rolled back).
   // 2. Improved throughput.
   await db.writeTransaction((tx) async {
-    await db.execute('INSERT INTO test_data(data) values(?)', ['Test3']);
-    await db.execute('INSERT INTO test_data(data) values(?)', ['Test4']);
+    await tx.execute('INSERT INTO test_data(data) values(?)', ['Test3']);
+    await tx.execute('INSERT INTO test_data(data) values(?)', ['Test4']);
   });
 
   await db.close();

example/basic_example.dart

@@ -29,8 +29,8 @@ void main() async {
   // 1. Atomic persistence (all updates are either applied or rolled back).
   // 2. Improved throughput.
   await db.writeTransaction((tx) async {
-    await db.execute('INSERT INTO test_data(data) values(?)', ['Test3']);
-    await db.execute('INSERT INTO test_data(data) values(?)', ['Test4']);
+    await tx.execute('INSERT INTO test_data(data) values(?)', ['Test3']);
+    await tx.execute('INSERT INTO test_data(data) values(?)', ['Test4']);
   });
 
   // Close database to release resources

test/basic_test.dart

@@ -175,6 +175,7 @@ void main() {
       // Note: In highly concurrent cases, it could exhaust the connection pool and cause a deadlock.
 
       await db.writeTransaction((tx) async {
+        // Use the parent zone to avoid the "recursive lock" error.
         await zone.fork().run(() async {
           await db.getAll('SELECT * FROM test_data');
         });
@@ -192,7 +193,7 @@ void main() {
         });
       });
 
-      // This would deadlock, since it shares a global write lock.
+      // Note: This would deadlock, since it shares a global write lock.
       // await db.writeTransaction((tx) async {
       //   await zone.fork().run(() async {
       //     await db.execute('SELECT * FROM test_data');