esp_http_client: Add comment for clearing location field in esp_http_client_prepare

components/esp_http_client/esp_http_client.c

@@ -512,6 +512,12 @@ static esp_err_t esp_http_client_prepare(esp_http_client_handle_t client)
     client->process_again = 0;
     client->response->data_process = 0;
     client->first_line_prepared = false;
+    /**
+     * Clear location field before making a new HTTP request. Location
+     * field should not be cleared in http_on_header* callbacks because
+     * callbacks can be invoked multiple times for same header, and
+     * hence can lead to data corruption.
+     */
     if (client->location != NULL) {
         free(client->location);
         client->location = NULL;