Remove ChunkedTransferMiddleware from default settings

docs/topics/downloader-middleware.rst

@@ -665,7 +665,13 @@ ChunkedTransferMiddleware
 
 .. class:: ChunkedTransferMiddleware
 
-   This middleware adds support for `chunked transfer encoding`_
+   This middleware adds support for `chunked transfer encoding`_.
+
+.. note::
+    This middleware is not enabled nor used by Scrapy downloader anymore.
+    In fact, Scrapy downloader has built-in support for chunked transfers,
+    so this middleware has no effect in practice.
+
 
 HttpProxyMiddleware
 -------------------

docs/topics/settings.rst

@@ -468,7 +468,6 @@ Default::
         'scrapy.downloadermiddlewares.redirect.RedirectMiddleware': 600,
         'scrapy.downloadermiddlewares.cookies.CookiesMiddleware': 700,
         'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware': 750,
-        'scrapy.downloadermiddlewares.chunked.ChunkedTransferMiddleware': 830,
         'scrapy.downloadermiddlewares.stats.DownloaderStats': 850,
         'scrapy.downloadermiddlewares.httpcache.HttpCacheMiddleware': 900,
     }

scrapy/settings/default_settings.py

@@ -102,7 +102,6 @@ DOWNLOADER_MIDDLEWARES_BASE = {
     'scrapy.downloadermiddlewares.redirect.RedirectMiddleware': 600,
     'scrapy.downloadermiddlewares.cookies.CookiesMiddleware': 700,
     'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware': 750,
-    'scrapy.downloadermiddlewares.chunked.ChunkedTransferMiddleware': 830,
     'scrapy.downloadermiddlewares.stats.DownloaderStats': 850,
     'scrapy.downloadermiddlewares.httpcache.HttpCacheMiddleware': 900,
     # Downloader side