fix(main.py): keep client consistent across calls + exponential backoff retry on ratelimit errors

litellm/llms/vertex_ai.py

@@ -6,11 +6,14 @@ import time
 from typing import Callable, Optional
 from litellm.utils import ModelResponse, Usage
 import litellm
+import httpx
 
 class VertexAIError(Exception):
     def __init__(self, status_code, message):
         self.status_code = status_code
         self.message = message
+        self.request = httpx.Request(method="POST", url="https://api.ai21.com/studio/v1/")
+        self.response = httpx.Response(status_code=status_code, request=self.request)
         super().__init__(
             self.message
         )  # Call the base class constructor with the parameters it needs