Call Transfer and Call hold

Hello dear freinds.

I have a question for the community before I will west my time on the following subjects.

Did anyone so far implement call transfer method using REFER message on the red5 phone plug in or Call hold Unhold functions?

call transfer is supported by the mjsip and 80% of the work already done - I can put some time to complete it, but first would like to check maybe someone allready did it and ready to controbute his code to the public.

Lior