Indication of DTMF send completion

Hi,

I'm using ToneController.Send() to send out DTMF tones.

I noticed that this method returns almost immediately, much before the DTMF is actually sent. My understanding is that this method only queues the request.

For example, if I send 20 DTMF in a loop then the send "completes" after ~20ms for all 20 DTMF, but actually they're sent in 14 seconds (~700ms between DTMFs).

The question is - how can I get an indication of the DMTF send completion (something like BeginSend/EndSend)?

Thanks,

Ron