config: add a read limit option to the connection.

By default, the read limit is never set by NewConnection.
When using the default pool dialer, a read limit of 512KB is set.
When the read limit option is set, all sockets passed to NewConnection have that read limit set.

pool.go

@@ -349,6 +349,13 @@ func (p *Pool) Connect(url string, opts ...ConnectOption) error {
 	}
 	dialFn := func(ctx context.Context) (types.Socket, error) {
 		socket, _, err := p.dialer.DialContext(ctx, url, hdr)
+
+		// Set a sane read limit when using the default dialer
+		// Can be overridden with ConnectionConfig.ReadLimit
+		if socket != nil {
+			socket.SetReadLimit(512 * 1024)
+		}
+
 		return socket, err
 	}