Type of call transfer - Attended or Unattended.
Assembly: Microsoft.Rtc.Collaboration (in Microsoft.Rtc.Collaboration.dll)
In the Unattended type, the call is terminated as soon as the transfer request is accepted by the remote participant. In the Attended type, the call monitors the success/failure notifications from the remote regarding how the transfer is being carried out. If the transfer succeeds, this call is terminated, otherwise the call is not affected.