rework client using async api

examples/client_basics.cc

@@ -8,7 +8,8 @@ int main() {
   WEBCC_LOG_INIT("", webcc::LOG_CONSOLE);
 
   webcc::ClientSession session;
-
+  session.set_connect_timeout(5);
+  session.set_read_timeout(5);
   session.Accept("application/json");
 
   webcc::ResponsePtr r;

examples/concurrency_test.cc

@@ -30,7 +30,7 @@ int main(int argc, const char* argv[]) {
     threads.emplace_back([&url]() {
       // NOTE: Each thread has its own client session.
       webcc::ClientSession session;
-      session.set_timeout(180);
+      session.set_read_timeout(180);
 
       try {
         LOG_USER("Start");

examples/file_downloader.cc

@@ -27,7 +27,10 @@ int main(int argc, char* argv[]) {
   webcc::ClientSession session;
 
   try {
-    auto r = session.Send(webcc::RequestBuilder{}.Get(url)(), true);
+    auto r = session.Send(webcc::RequestBuilder{}.Get(url)(), true,
+                          [](std::size_t length, std::size_t total_length) {
+      std::cout << "Progress " << length << " / " << total_length << std::endl;
+    });
 
     if (auto file_body = r->file_body()) {
       file_body->Move(path);