comfort tone on attended transfer

[Chris Barron]

All,
this question was possibly asked in a different way in 2014. When completing an attended transfer its normal for the recipient of the transferred call (c party) to hear a comfort tone warning them the caller is now on the line.
I can't see anywhere this is described - does it exist or is it in development?
I have two possible alternatives
use DTMF commands to action the transfer in the hope that the C party will hear.
use conferencing transfer so the transferee introduces the call ?