Update types in order to take empty responses into account.

Author: Julien Salinas

README.md

@@ -163,6 +163,8 @@ If you are making asynchronous requests, you will always receive a quick respons
 client.asyncResult('https://api.nlpcloud.io/v1/get-async-result/21718218-42e8-4be9-a67f-b7e18e03b436')
 ```
 
+The above returns an object is the response is available. It returns an empty response otherwise (`null`).
+
 ### Automatic Speech Recognition (Speech to Text) Endpoint
 
 Call the `asr()` method and pass the following arguments:

dist/index.d.ts

@@ -57,7 +57,7 @@ declare class Client {
             error_detail: string;
             content: string;
         };
-    }>;
+    } | null >;
 
     chatbot(params: {
         input: string,