Parallelize individual table reads/writes for modest gains.

src/test.rs

@@ -34,10 +34,20 @@ async fn test_mysql() -> Result<(), Error> {
     let pool = TestPool::try_new().await?;
     crate::load_data(&pool).await?;
     time_test::time_test!();
-    crate::convert_data(&pool, "employees").await?;
-    crate::convert_data(&pool, "departments").await?;
-    <mysql_async::Pool as Clone>::clone(&pool)
-        .disconnect()
-        .await?;
+    let tables = vec!["employees", "departments"];
+    let mut handles: Vec<tokio::task::JoinHandle<Result<(), crate::Error>>> = vec![];
+    for table in tables {
+        handles.push(tokio::spawn({
+            let pool = pool.clone();
+            let table = table.to_string();
+            async move {
+                crate::convert_data(&pool, &table).await?;
+                Ok(())
+            }
+        }));
+    }
+    for handle in handles {
+        let _ = handle.await?;
+    }
     Ok(())
 }