source-zendesk-support-native: reduce memory usage by streaming incremental export resources

Using the new `http.request_object_stream` to stream incremental export
resources signficantly reduces the memory usage of the connector, even
when using the max page size of 1000.

Author: Alex-Bair

source-zendesk-support-native/poetry.lock

@@ -313,20 +313,21 @@ async def backfill_satisfaction_ratings(
     yield end
 
 
-async def _make_incremental_cursor_export_request(
+async def _fetch_top_level_fields(
     http: HTTPSession,
     url: str,
     params: dict[str, str | int],
     response_model: type[IncrementalCursorExportResponse],
     log: Logger,
-) -> IncrementalCursorExportResponse:
+) -> tuple[str | None, bool]:
     # Instead of using Pydantic's model_validate_json that uses json.loads internally,
     # use json.JSONDecoder().raw_decode to reduce memory overhead when processing the response.
     raw_response_bytes = await http.request(log, url, params=params)
     obj, _ = json.JSONDecoder().raw_decode(raw_response_bytes.decode('utf-8'))
     # model_construct is used to avoid validating & transforming all resources within large response bodies at once
     # to reduce memory overhead. Instead, resources are validated & transformed one-by-one as they are yielded.
-    return response_model.model_construct(**obj)
+    response =  response_model.model_construct(**obj)
+    return (response.after_cursor, response.end_of_stream)
 
 
 async def _fetch_incremental_cursor_export_resources(
@@ -360,21 +361,13 @@ async def _fetch_incremental_cursor_export_resources(
         params["cursor"] = _base64_encode(cursor)
 
     while True:
-        response = await _make_incremental_cursor_export_request(http, url, params, response_model, log)
-
-        next_page_cursor = response.after_cursor
-        end_of_stream = response.end_of_stream
-
-        next_page_cursor = response.after_cursor
-        end_of_stream = response.end_of_stream
+        next_page_cursor, end_of_stream = await _fetch_top_level_fields(http, url, params, response_model, log)
 
         if next_page_cursor is None:
             return
 
-        for resource in response.resources:
-            # Since _make_incremental_cursor_export_request does not validate & transform all resources at once,
-            # we validate them one-by-one as they're yielded.
-            yield TimestampedResource.model_validate(resource)
+        async for resource in http.request_object_stream(log, TimestampedResource, f"{name}.item", url, params=params):
+            yield resource
 
         yield _base64_decode(next_page_cursor)