Only update stats and socket events if operation is successful

We were not checking the result of the connect, send, recv operations.
We assumed that they were successful and treated them as successful, which
gave at least wrong stats and possibly other minor problems too.

nano/node/socket.cpp

@@ -62,7 +62,10 @@ void nano::socket::async_connect (nano::tcp_endpoint const & endpoint_a, std::fu
 	this_l->tcp_socket.async_connect (endpoint_a,
 	boost::asio::bind_executor (this_l->strand,
 	[this_l, callback = std::move (callback_a), endpoint_a] (boost::system::error_code const & ec) {
-		this_l->stop_timer ();
+		if (!ec)
+		{
+			this_l->stop_timer ();
+		}
 		this_l->remote = endpoint_a;
 		callback (ec);
 	}));
@@ -80,9 +83,12 @@ void nano::socket::async_read (std::shared_ptr<std::vector<uint8_t>> const & buf
 				boost::asio::async_read (this_l->tcp_socket, boost::asio::buffer (buffer_a->data (), size_a),
 				boost::asio::bind_executor (this_l->strand,
 				[this_l, buffer_a, cbk = std::move (callback)] (boost::system::error_code const & ec, std::size_t size_a) {
-					this_l->node.stats.add (nano::stat::type::traffic_tcp, nano::stat::dir::in, size_a);
-					this_l->stop_timer ();
-					this_l->update_last_receive_time ();
+					if (!ec)
+					{
+						this_l->node.stats.add (nano::stat::type::traffic_tcp, nano::stat::dir::in, size_a);
+						this_l->stop_timer ();
+						this_l->update_last_receive_time ();
+					}
 					cbk (ec, size_a);
 				}));
 			}));
@@ -109,8 +115,11 @@ void nano::socket::async_write (nano::shared_const_buffer const & buffer_a, std:
 				boost::asio::bind_executor (this_l->strand,
 				[buffer_a, cbk = std::move (callback), this_l] (boost::system::error_code ec, std::size_t size_a) {
 					--this_l->queue_size;
-					this_l->node.stats.add (nano::stat::type::traffic_tcp, nano::stat::dir::out, size_a);
-					this_l->stop_timer ();
+					if (!ec)
+					{
+						this_l->node.stats.add (nano::stat::type::traffic_tcp, nano::stat::dir::out, size_a);
+						this_l->stop_timer ();
+					}
 					if (cbk)
 					{
 						cbk (ec, size_a);