incomingBytes func(n int64) // Record incoming bytes.
	outgoingBytes func(n int64) // Record outgoing bytes.
	trace         *tracer       // tracer for this connection.
	baseFlags     Flags
	outBytes      atomic.Int64
	inBytes       atomic.Int64
	inMessages    atomic.Int64
	outMessages   atomic.Int64

	// For testing only
	debugInConn   net.Conn
	debugOutConn  net.Conn