event loop: re-implement based on esp_event library

Includes ds2ds unit test fix, iperf example test fix

components/tcpip_adapter/include/tcpip_adapter.h

@@ -168,6 +168,12 @@ typedef struct {
     tcpip_adapter_ip6_info_t ip6_info;  /*!< IPv6 address of the interface */
 } ip_event_got_ip6_t;
 
+/** Event structure for IP_EVENT_AP_STAIPASSIGNED event */
+typedef struct {
+    ip4_addr_t ip; /*!< IP address which was assigned to the station */
+} ip_event_ap_staipassigned_t;
+
+
 /**
  * @brief  Initialize the underlying TCP/IP stack
  *
@@ -686,6 +692,40 @@ esp_err_t tcpip_adapter_get_netif(tcpip_adapter_if_t tcpip_if, void ** netif);
  */
 bool tcpip_adapter_is_netif_up(tcpip_adapter_if_t tcpip_if);
 
+
+/**
+ * @brief  Install default event handlers for Ethernet interface
+ * @return
+ *      - ESP_OK on success
+ *      - one of the errors from esp_event on failure
+ */
+esp_err_t tcpip_adapter_set_default_eth_handlers();
+
+/**
+ * @brief Uninstall default event handlers for Ethernet interface
+ * @return
+ *      - ESP_OK on success
+ *      - one of the errors from esp_event on failure
+ */
+esp_err_t tcpip_adapter_clear_default_eth_handlers();
+
+/**
+ * @brief  Install default event handlers for Wi-Fi interfaces (station and AP)
+ * @return
+ *      - ESP_OK on success
+ *      - one of the errors from esp_event on failure
+ */
+esp_err_t tcpip_adapter_set_default_wifi_handlers();
+
+/**
+ * @brief  Uninstall default event handlers for Wi-Fi interfaces (station and AP)
+ * @return
+ *      - ESP_OK on success
+ *      - one of the errors from esp_event on failure
+ */
+esp_err_t tcpip_adapter_clear_default_wifi_handlers();
+
+
 #ifdef __cplusplus
 }
 #endif