[in] When calling this method on an external socket, this
sockaddr structure should contain the target address for a
UDP datagram. When calling this method on an internal socket, this
parameter should contain the address of the datagram source. This
is typically the Internet address from which the pIOBuffer
packet originated. That is, the internal socket is associated with
the Internet address of the pIOBuffer packet.
[in] Length, in bytes, of the Address parameter.
[in] Pointer to an IFWXIOCompletion interface that
is notified when the send operation is completed. Set this
parameter to NULL if notification is not required.