set WINHTTP_OPTION_REQUIRE_STREAM_END on the session handle

Author: antonfirsov

src/libraries/System.Net.Http.WinHttpHandler/src/System/Net/Http/WinHttpHandler.cs

@@ -1120,6 +1120,7 @@ private void SetSessionHandleOptions(SafeWinHttpHandle sessionHandle)
             SetSessionHandleTimeoutOptions(sessionHandle);
             SetDisableHttp2StreamQueue(sessionHandle);
             SetTcpKeepalive(sessionHandle);
+            SetRequireStreamEnd(sessionHandle);
         }
 
         private unsafe void SetTcpKeepalive(SafeWinHttpHandle sessionHandle)
@@ -1145,6 +1146,27 @@ private unsafe void SetTcpKeepalive(SafeWinHttpHandle sessionHandle)
             }
         }
 
+        private void SetRequireStreamEnd(SafeWinHttpHandle sessionHandle)
+        {
+            if (WinHttpTrailersHelper.OsSupportsTrailers)
+            {
+                // Setting WINHTTP_OPTION_REQUIRE_STREAM_END to TRUE is needed for WinHttp to read trailing headers
+                // in case the response has Content-Lenght defined.
+                // According to the WinHttp team, the feature-detection logic in WinHttpTrailersHelper.OsSupportsTrailers
+                // should also indicate the support of WINHTTP_OPTION_REQUIRE_STREAM_END.
+                // WINHTTP_OPTION_REQUIRE_STREAM_END doesn't have effect on HTTP 1.1 requests, therefore it's safe to set it on
+                // the session handle so it is inhereted by all request handles.
+                uint optionData = 1;
+                if (!Interop.WinHttp.WinHttpSetOption(sessionHandle, Interop.WinHttp.WINHTTP_OPTION_REQUIRE_STREAM_END, ref optionData))
+                {
+                    if (NetEventSource.Log.IsEnabled())
+                    {
+                        NetEventSource.Info(this, "Failed to enable WINHTTP_OPTION_REQUIRE_STREAM_END error code: " + Marshal.GetLastWin32Error());
+                    }
+                }
+            }
+        }
+
         private void SetSessionHandleConnectionOptions(SafeWinHttpHandle sessionHandle)
         {
             uint optionData = (uint)_maxConnectionsPerServer;
@@ -1534,22 +1556,6 @@ private void SetRequestHandleHttp2Options(SafeWinHttpHandle requestHandle, Versi
             {
                 if (NetEventSource.Log.IsEnabled()) NetEventSource.Info(this, "HTTP/2 option not supported");
             }
-
-            if (requestVersion == HttpVersion20 && WinHttpTrailersHelper.OsSupportsTrailers)
-            {
-                // Setting WINHTTP_OPTION_REQUIRE_STREAM_END to TRUE is needed for WinHttp to read trailing headers
-                // in case the response has Content-Lenght defined.
-                // According to the WinHttp team, the feature-detection logic in WinHttpTrailersHelper.OsSupportsTrailers
-                // should also indicate the support of WINHTTP_OPTION_REQUIRE_STREAM_END.
-                optionData = 1;
-                if (!Interop.WinHttp.WinHttpSetOption(requestHandle, Interop.WinHttp.WINHTTP_OPTION_REQUIRE_STREAM_END, ref optionData))
-                {
-                    if (NetEventSource.Log.IsEnabled())
-                    {
-                        NetEventSource.Info(this, "Failed to enable WINHTTP_OPTION_REQUIRE_STREAM_END error code: " + Marshal.GetLastWin32Error());
-                    }
-                }
-            }
         }
 
         private void SetWinHttpOption(SafeWinHttpHandle handle, uint option, ref uint optionData)