* \param addr Network mac address, e.g., "01:23:45:67:89:ab", "89:ab" or "".
* If \p addr is HH:HH, it's treated as if it were 00:50:c2:85:HH:HH
* "" will autoselect a USRP2 if there is only a single one on the local ethernet.
+ * \param rx_bufsize is the length in bytes of the kernel networking buffer to allocate.
*/
static sptr make(const std::string &ifc, const std::string &addr="", size_t rx_bufsize=0);