Add comment to explain the nasty details

src/providers/wfs/qgswfsrequest.cpp

@@ -133,8 +133,6 @@ bool QgsWfsRequest::sendGET( const QUrl &url, bool synchronous, bool forceRefres
     bool success = true;
     mReply = QgsNetworkAccessManager::instance()->get( request );
 
-    Q_ASSERT( QThread::currentThread() == mReply->thread() );
-
     mReply->setReadBufferSize( READ_BUFFER_SIZE_HINT );
     if ( !mUri.auth().setAuthorizationReply( mReply ) )
     {
@@ -145,6 +143,9 @@ bool QgsWfsRequest::sendGET( const QUrl &url, bool synchronous, bool forceRefres
     }
     else
     {
+      // We are able to use direct connection here, because we
+      // * either run on the thread mReply lives in, so DirectConnection is standard and safe anyway (if it is not the main thread)
+      // * or the owner thread of mReply is currently not doing anything because it's blocked in future.waitForFinished() (if it is the main thread)
       connect( mReply, &QNetworkReply::finished, this, &QgsWfsRequest::replyFinished, Qt::DirectConnection );
       connect( mReply, &QNetworkReply::downloadProgress, this, &QgsWfsRequest::replyProgress, Qt::DirectConnection );