code: public void debug( Marker marker, String msg, Throwable t )
      {
          if( m_delegate.isDebugEnabled() )
          {
              setMDCMarker( marker );
              m_delegate.debug( msg, t );
              resetMDCMarker();
          }
      }
docs: This method is similar to {@link #debug(String, Throwable)} method except that the
  marker data is also taken into consideration.
  
  @param marker the marker data specific to this log statement
  @param msg    the message accompanying the exception
  @param t      the exception (throwable) to log