internally use and assume the multi interface. The select()-loop should use
curl_multi_socket().
+ * curl_multi_handle_control() - this can control the easy handle (while)
+ added to a multi handle in various ways:
+ o RESTART, unconditionally restart this easy handle's transfer from the
+ start, re-init the state
+ o RESTART_COMPLETED, restart this easy handle's transfer but only if the
+ existing transfer has already completed and it is in a "finished state".
+ o STOP, just stop this transfer and consider it completed
+ o PAUSE?
+ o RESUME?
+
DOCUMENTATION
* More and better