Sanity tests related to number of packets, packet size & packet priority

Summary:
related to T12015
- add tests related to sending/receiving really big packets
- add tests related to receiving multiple packets at once
- send_big_publish fails in the testing environment, but it works fine in real life

Reviewers: ivica

Reviewed By: ivica

Subscribers: miljen, iljazovic

Differential Revision: https://repo.mireo.local/D27652

include/async_mqtt5/impl/ping_op.hpp

@@ -94,12 +94,16 @@ public:
 		);
 	}
 
-	void operator()(on_pingreq, error_code) {
+	void operator()(on_pingreq, error_code ec) {
 		get_cancellation_slot().clear();
 
-		if (_cancellation_state.cancelled() == asio::cancellation_type::terminal)
+		if (
+			_cancellation_state.cancelled() == asio::cancellation_type::terminal ||
+			ec == asio::error::no_recovery
+		)
 			return;
 
+		_cancellation_state.clear();
 		perform();
 	}