Move the rewind code closer to the reason why we need to rewind

We only need to rewind because we call `read_body_stream`. Since
that method is only called in one place, move the rewing to inside it.

Gemfile.lock

@@ -413,7 +413,7 @@ GEM
       pg (>= 1.1, < 2.0)
     raabro (1.4.0)
     racc (1.8.0)
-    rack (3.0.11)
+    rack (3.1.3)
     rack-cache (1.15.0)
       rack (>= 0.4)
     rack-session (2.0.0)

actionpack/lib/action_dispatch/http/request.rb

@@ -340,7 +340,6 @@ def server_software
     def raw_post
       unless has_header? "RAW_POST_DATA"
         set_header("RAW_POST_DATA", read_body_stream)
-        body_stream.rewind if body_stream.respond_to?(:rewind)
       end
       get_header "RAW_POST_DATA"
     end
@@ -467,9 +466,27 @@ def default_session
       end
 
       def read_body_stream
-        body_stream.rewind if body_stream.respond_to?(:rewind)
-        return body_stream.read if headers.key?("Transfer-Encoding") # Read body stream until EOF if "Transfer-Encoding" is present
-        body_stream.read(content_length)
+        reset_stream(body_stream) do
+          if headers.key?("Transfer-Encoding")
+            body_stream.read # Read body stream until EOF if "Transfer-Encoding" is present
+          else
+            body_stream.read(content_length)
+          end
+        end
+      end
+
+      def reset_stream(body_stream)
+        if body_stream.respond_to?(:rewind)
+          body_stream.rewind
+
+          content = yield
+
+          body_stream.rewind
+
+          content
+        else
+          yield
+        end
       end
   end
 end