Add examples for MemoryStorage (gluesql#499)

pkg/rust/examples/memory_storage_usage.rs

@@ -0,0 +1,62 @@
+#[cfg(feature = "memory-storage")]
+mod api_usage {
+    use gluesql::{memory_storage::MemoryStorage, prelude::Glue};
+
+    fn memory_basic() {
+        let storage = MemoryStorage::default();
+        let mut glue = Glue::new(storage);
+
+        glue.execute("DROP TABLE IF EXISTS api_test");
+
+        glue.execute(
+            "CREATE TABLE api_test (
+                id INTEGER,
+                name TEXT,
+                nullable TEXT NULL,
+                is BOOLEAN
+            )",
+        );
+
+        glue.execute(
+            "INSERT INTO api_test (
+                id,
+                name,
+                nullable,
+                is
+            ) VALUES
+                (1, 'test1', 'not null', TRUE),
+                (2, 'test2', NULL, FALSE)",
+        );
+    }
+
+    fn memory_basic_async() {
+        use futures::executor::block_on;
+
+        let storage = MemoryStorage::default();
+        let mut glue = Glue::new(storage);
+
+        block_on(async {
+            glue.execute_async("DROP TABLE IF EXISTS api_test").await;
+
+            glue.execute_async(
+                "CREATE TABLE api_test (
+                    id INTEGER,
+                    name TEXT,
+                    nullable TEXT NULL,
+                    is BOOLEAN
+                )",
+            )
+            .await;
+        });
+    }
+
+    pub fn run() {
+        memory_basic();
+        memory_basic_async();
+    }
+}
+
+fn main() {
+    #[cfg(feature = "memory-storage")]
+    api_usage::run();
+}