feat: exports undici (#554)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **Bug Fixes**
- Improved error handling and diagnostics publishing for fetch
operations, ensuring errors are reported through the correct channel.

- **New Features**
- Enhanced type definitions with new types for better type safety:
`BodyInit`, `ResponseInit`, `Headers`, and `FormData`.
- Optimized handling of HTTP requests with caching for socket-based
clients.

- **Documentation**
- Updated export statements to maintain compatibility with existing
libraries while enhancing functionality.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

src/fetch.ts

@@ -223,11 +223,11 @@ export class FetchFactory {
         res = await UndiciFetch(input, init);
       });
     } catch (e: any) {
-      channels.response.publish({
+      channels.fetchResponse.publish({
         fetch: fetchMeta,
         error: e,
       } as FetchResponseDiagnosticsMessage);
-      channels.fetchResponse.publish({
+      channels.response.publish({
         request: reqMeta,
         response: urllibResponse,
         error: e,

src/index.ts

@@ -44,7 +44,8 @@ export {
   MockAgent, ProxyAgent, Agent, Dispatcher,
   setGlobalDispatcher, getGlobalDispatcher,
   Request, RequestInfo, RequestInit,
-  Response,
+  Response, BodyInit, ResponseInit,
+  Headers, FormData,
 } from 'undici';
 // HttpClient2 is keep compatible with urllib@2 HttpClient2
 export {