A special version of wx.LogChain which uses itself as the new log target.
It forwards log messages to the previously installed one in addition to processing them itself.
Unlike wx.LogChain which is usually used directly as is, this class must be derived from to implement Log.DoLog and/or Log.DoLogString methods.
wx.LogInterposer destroys the previous log target in its destructor. If you don’t want this to happen, use wx.LogInterposerTemp instead.