tlsConfig          *tls.Config
	blockConnect       chan struct{}

	incomingBytes func(n int64) // Record incoming bytes.
	outgoingBytes func(n int64) // Record outgoing bytes.
	trace         *tracer       // tracer for this connection.
	baseFlags     Flags

	// For testing only
	debugInConn  net.Conn
	debugOutConn net.Conn
	addDeadline  time.Duration
	connMu       sync.Mutex
}