struct SECURITY_LOGON_SESSION_DATA {

Structure SECURITY_LOGON_SESSION_DATA

private struct SECURITY_LOGON_SESSION_DATA

      SECURITY_LOGON_SESSION_DATA data = (SECURITY_LOGON_SESSION_DATA)Marshal.PtrToStructure(sessionData, typeof(SECURITY_LOGON_SESSION_DATA));

      LsaFreeReturnBuffer(sessionData);   //free the SECURITY_LOGON_SESSION_DATA memory in the struct