typedef int vls_handle_t;
vls_handle_t vls_create (uint8_t proto, uint8_t is_nonblocking);
-int vls_shutdown (vls_handle_t vlsh);
+int vls_shutdown (vls_handle_t vlsh, int how);
int vls_close (vls_handle_t vlsh);
int vls_bind (vls_handle_t vlsh, vppcom_endpt_t * ep);
int vls_listen (vls_handle_t vlsh, int q_len);