examples/protocols/esp_http_client: Add example for asynchronous HTTP request

examples/protocols/esp_http_client/main/esp_http_client_example.c

@@ -342,6 +342,38 @@ static void http_perform_as_stream_reader()
     free(buffer);
 }
 
+static void https_async()
+{
+    esp_http_client_config_t config = {
+        .url = "https://postman-echo.com/post",
+        .event_handler = _http_event_handler,
+        .is_async = true,
+        .timeout_ms = 5000,
+    };
+    esp_http_client_handle_t client = esp_http_client_init(&config);
+    esp_err_t err;
+    const char *post_data = "Using a Palantír requires a person with great strength of will and wisdom. The Palantíri were meant to "
+                            "be used by the Dúnedain to communicate throughout the Realms in Exile. During the War of the Ring, "
+                            "the Palantíri were used by many individuals. Sauron used the Ithil-stone to take advantage of the users "
+                            "of the other two stones, the Orthanc-stone and Anor-stone, but was also susceptible to deception himself.";
+    esp_http_client_set_method(client, HTTP_METHOD_POST);
+    esp_http_client_set_post_field(client, post_data, strlen(post_data));
+    while (1) {
+        err = esp_http_client_perform(client);
+        if (err != ESP_ERR_HTTP_EAGAIN) {
+            break;
+        }
+    }
+    if (err == ESP_OK) {
+        ESP_LOGI(TAG, "HTTPS Status = %d, content_length = %d",
+                esp_http_client_get_status_code(client),
+                esp_http_client_get_content_length(client));
+    } else {
+        ESP_LOGE(TAG, "Error perform http request %s", esp_err_to_name(err));
+    }
+    esp_http_client_cleanup(client);
+}
+
 static void http_test_task(void *pvParameters)
 {
     app_wifi_wait_connected();
@@ -356,6 +388,7 @@ static void http_test_task(void *pvParameters)
     http_redirect_to_https();
     http_download_chunk();
     http_perform_as_stream_reader();
+    https_async();
     ESP_LOGI(TAG, "Finish http example");
     vTaskDelete(NULL);
 }