update fragment handling

src/api-session.ts

-import { PromptOptions, Random, Session } from 'koishi';
+import {
+  Fragment,
+  PromptOptions,
+  Random,
+  segment,
+  SendOptions,
+  Session,
+} from 'koishi';
 import ApiBot from './index';
 import { Prompt } from './def/prompt';
 
-
 export class ApiSession extends Session {
   storedMessages: string[] = [];
   private midResolver: () => void;
@@ -39,8 +45,13 @@ export class ApiSession extends Session {
     }
   }
 
-  async send(content: string) {
-    this.storedMessages.push(content);
+  async send(content: Fragment, options: SendOptions = {}) {
+    if (!content) return;
+    options.session = this;
+    const children = await this.transform(segment.normalize(content));
+    this.storedMessages.push(
+      children.map((child) => child.toString()).join(''),
+    );
     return [Random.id()];
   }