XmTransferStartRequest begins a MULTIPLE request.
The MULTIPLE request may contain one or more calls to
XmTransferValue. Your application concludes a
MULTIPLE request by calling XmTransferSendRequest.
XmTransferStartRequest is typically called by a destination callback
or by a transfer procedure.
transfer_id
Specifies a unique indentifier for the data transfer operation.
You should use the transfer_id passed in the
XmDestinationCallbackStruct or XmSelectionCallbackStruct.