chore(rsc): use prerender in ssg example (#758)

Author: hi-ogawa

packages/plugin-rsc/examples/ssg/src/framework/entry.ssr.tsx

@@ -1,6 +1,7 @@
 import { createFromReadableStream } from '@vitejs/plugin-rsc/ssr'
 import React from 'react'
 import { renderToReadableStream } from 'react-dom/server.edge'
+import { prerender } from 'react-dom/static.edge'
 import { injectRSCPayload } from 'rsc-html-stream/server'
 import type { RscPayload } from './shared'
 
@@ -18,15 +19,19 @@ export async function renderHtml(
     const root = React.use(payload).root
     return root
   }
-
   const bootstrapScriptContent =
     await import.meta.viteRsc.loadBootstrapScriptContent('index')
 
-  const htmlStream = await renderToReadableStream(<SsrRoot />, {
-    bootstrapScriptContent,
-  })
+  let htmlStream: ReadableStream<Uint8Array>
   if (options?.ssg) {
-    await htmlStream.allReady
+    const prerenderResult = await prerender(<SsrRoot />, {
+      bootstrapScriptContent,
+    })
+    htmlStream = prerenderResult.prelude
+  } else {
+    htmlStream = await renderToReadableStream(<SsrRoot />, {
+      bootstrapScriptContent,
+    })
   }
 
   let responseStream: ReadableStream<Uint8Array> = htmlStream