retry on transport errors (#139)

fauna/http/httpx_client.py

@@ -68,15 +68,27 @@ def request(
     except httpx.InvalidURL as e:
       raise ClientError("Invalid URL Format") from e
 
+    try:
+      return HTTPXResponse(self._send_with_retry(3, request))
+    except (httpx.HTTPError, httpx.InvalidURL) as e:
+      raise NetworkError("Exception re-raised from HTTP request") from e
+
+  def _send_with_retry(
+      self,
+      retryCount: int,
+      request: httpx.Request,
+  ) -> httpx.Response:
     try:
       response = self._c.send(
           request,
           stream=False,
       )
-    except (httpx.HTTPError, httpx.InvalidURL) as e:
-      raise NetworkError("Exception re-raised from HTTP request") from e
-
-    return HTTPXResponse(response)
+      return response
+    except httpx.TransportError as e:
+      if retryCount == 0:
+        raise e
+      else:
+        return self._send_with_retry(retryCount - 1, request)
 
   def stream(
       self,