rohc mode

hello Didier,

          After reading your lib 1.7.0 , I find :
1 . if the received feedbacks change rohc mode (U-mode ,o-mode or R-mode) in compressor, but it do not send the mode changing to the decompressor immediately , and decompressor mode can not be changed at this time. is it right? It is only changed when do_change_mode is ture or U-mode.
2.can the decompressor mode can be changed from O-mode to U-mode? if so ,when?
3.why the R-mode is not implemented yet, it is not difficult, I think the R-mode only has more feedbacks than the O-mode?

I am looking forward to receiving your answers,Thank you .

Regards,
regularA