fix missing file close

src/NodeFileSystemWriteableFileStream.ts

@@ -39,6 +39,7 @@ export default class NodeFileSystemWritableFileStream extends WritableStream imp
         }
         const file = await asyncfs.open(this.#name,'r+')
         await file.write((wdata as Uint8Array), null, wsize, this.#seek_position)
+        await file.close()
         this.#seek_position = pseek_position
     }
 }