Gracefully shutdown Websocket and TLS streams

Summary:
Resolves #18
Ref T15241

Reviewers: ivica

Reviewed By: ivica

Subscribers: korina, miljen

Maniphest Tasks: T15241

Differential Revision: https://repo.mireo.local/D33395

test/integration/send_publish.cpp

@@ -533,7 +533,7 @@ BOOST_FIXTURE_TEST_CASE(cancel_resending_publish, shared_test_data) {
             [&handlers_called, &c](error_code ec, reason_code rc, puback_props) {
                 ++handlers_called;
 
-                BOOST_TEST(ec = asio::error::operation_aborted);
+                BOOST_TEST(ec == asio::error::operation_aborted);
                 BOOST_TEST(rc == reason_codes::empty);
 
                 c.cancel();