Logging waiting for XML log file

(cherry picked from commit 70715e5b8c56291c9fd35d02764fb1753c9498f9)

Source commit: bebf505cd247daccf9e05ad079b35af10bce1059

dotnet/Session.cs

@@ -271,6 +271,8 @@ namespace WinSCP
                     log = openCommand + log;
                     WriteCommand(command, log);
 
+                    Logger.WriteLine("Waiting for XML log file");
+
                     // Wait until the log file gets created or WinSCP terminates (in case of fatal error)
                     do
                     {
@@ -323,6 +325,8 @@ namespace WinSCP
 
                     } while (!File.Exists(XmlLogPath));
 
+                    Logger.WriteLine("XML log file created");
+
                     _logReader = new SessionLogReader(this);
 
                     _logReader.WaitForNonEmptyElement("session", LogReadFlags.ThrowFailures);